std::allocator_traits< typename >(3)

NAME
std::allocator_traits< typename > - Uniform interface to all allocator types.

SYNOPSIS

#include <memory>

Inherits __allocator_traits_base.

  Public Types
typedef _Alloc allocator_type
The allocator type.
using const_pointer
The allocator's const pointer type.
using const_void_pointer
The allocator's const void pointer type.
using difference_type
The allocator's difference type.
using is_always_equal
Whether all instances of the allocator type compare equal.
using pointer
The allocator's pointer type.
using propagate_on_container_copy_assignment
How the allocator is propagated on copy assignment.
using propagate_on_container_move_assignment
How the allocator is propagated on move assignment.
using propagate_on_container_swap
How the allocator is propagated on swap.
template<typename _Tp > using rebind_alloc
template<typename _Tp > using rebind_traits
using size_type
The allocator's size type.
typedef _Alloc::value_type value_type
The allocated type.
using void_pointer
The allocator's void pointer type.

  Static Public Member Functions
static constexpr pointer allocate (_Alloc &__a, size_type __n)
Allocate memory.
static constexpr pointer allocate (_Alloc &__a, size_type __n, const_void_pointer __hint)
Allocate memory.
template<typename _Tp , typename... _Args>
requires __can_construct<_Alloc, _Tp, _Args...>static constexpr void construct (_Alloc &__a, _Tp *__p, _Args &&... __args) noexcept(_S_nothrow_construct< _Tp, _Args... >())"
Construct an object of type _Tp
static constexpr void deallocate (_Alloc &__a, pointer __p, size_type __n)
Deallocate memory.
template<typename _Tp > static constexpr void destroy (_Alloc &__a, _Tp *__p) noexcept(_S_nothrow_destroy< _Tp >())
Destroy an object of type _Tp.
static constexpr size_type max_size (const _Alloc &__a) noexcept
The maximum supported allocation size.
static constexpr _Alloc select_on_container_copy_construction (const _Alloc &__rhs)
Obtain an allocator to use when copying a container.

Detailed Description

  template<typename>
struct std::allocator_traits< typename >"Uniform interface to all allocator types.

Since
    C++11

Member Typedef Documentation

  template<typename > typedef _Alloc std::allocator_traits< typename >::allocator_type

The allocator type.

  template<typename > using std::allocator_traits< typename >::const_pointer

The allocator's const pointer type. Alloc::const_pointer if that type exists, otherwise pointer_traits<pointer>::rebind<const value_type>

  template<typename > using std::allocator_traits< typename >::const_void_pointer

The allocator's const void pointer type. Alloc::const_void_pointer if that type exists, otherwise pointer_traits<pointer>::rebind<const void>

  template<typename > using std::allocator_traits< typename >::difference_type

The allocator's difference type. Alloc::difference_type if that type exists, otherwise pointer_traits<pointer>::difference_type

  template<typename > using std::allocator_traits< typename >::is_always_equal

Whether all instances of the allocator type compare equal. Alloc::is_always_equal if that type exists, otherwise is_empty<Alloc>::type

  template<typename > using std::allocator_traits< typename >::pointer

The allocator's pointer type. Alloc::pointer if that type exists, otherwise value_type*

  template<typename > using std::allocator_traits< typename >::propagate_on_container_copy_assignment

How the allocator is propagated on copy assignment. Alloc::propagate_on_container_copy_assignment if that type exists, otherwise false_type

  template<typename > using std::allocator_traits< typename >::propagate_on_container_move_assignment

How the allocator is propagated on move assignment. Alloc::propagate_on_container_move_assignment if that type exists, otherwise false_type

  template<typename > using std::allocator_traits< typename >::propagate_on_container_swap

How the allocator is propagated on swap. Alloc::propagate_on_container_swap if that type exists, otherwise false_type

  template<typename > using std::allocator_traits< typename >::size_type

The allocator's size type. Alloc::size_type if that type exists, otherwise make_unsigned<difference_type>::type

  template<typename > typedef _Alloc::value_type std::allocator_traits< typename >::value_type

The allocated type.

  template<typename > using std::allocator_traits< typename >::void_pointer

The allocator's void pointer type. Alloc::void_pointer if that type exists, otherwise pointer_traits<pointer>::rebind<void>

Member Function Documentation

  template<typename > static constexpr pointer std::allocator_traits< typename >::allocate (_Alloc & __a, size_type __n) [inline], [static], [nodiscard], [constexpr]

Allocate memory.

Parameters
    __a An allocator.
    __n The number of objects to allocate space for.

Calls a.allocate(n)

  template<typename > static constexpr pointer std::allocator_traits< typename >::allocate (_Alloc & __a, size_type __n, const_void_pointer __hint) [inline], [static], [nodiscard], [constexpr]

Allocate memory.

Parameters
    __a An allocator.
    __n The number of objects to allocate space for.
    __hint Aid to locality.

Returns
    Memory of suitable size and alignment for n objects of type value_type

Returns a.allocate(n, hint) if that expression is well-formed, otherwise returns a.allocate(n)

  template<typename > template<typename _Tp , typename... _Args>
requires __can_construct<_Alloc, _Tp, _Args...>static constexpr void std::allocator_traits< typename >::construct (_Alloc & __a, _Tp * __p, _Args &&... __args) [inline], [static], [constexpr], [noexcept]"

Construct an object of type _Tp

Parameters
    __a An allocator.
    __p Pointer to memory of suitable size and alignment for Tp
    __args Constructor arguments.

Calls __a.construct(__p, std::forward<Args>(__args)...) if that expression is well-formed, otherwise uses placement-new to construct an object of type _Tp at location __p from the arguments __args...

References std::_Construct(), and std::forward().

  template<typename > static constexpr void std::allocator_traits< typename >::deallocate (_Alloc & __a, pointer __p, size_type __n) [inline], [static], [constexpr]

Deallocate memory.

Parameters
    __a An allocator.
    __p Pointer to the memory to deallocate.
    __n The number of objects space was allocated for.

Calls a.deallocate(p, n)

  template<typename > template<typename _Tp > static constexpr void std::allocator_traits< typename >::destroy (_Alloc & __a, _Tp * __p) [inline], [static], [constexpr], [noexcept]

Destroy an object of type _Tp.

Parameters
    __a An allocator.
    __p Pointer to the object to destroy

Calls __a.destroy(__p) if that expression is well-formed, otherwise calls __p->~_Tp()

References std::_Destroy().

  template<typename > static constexpr size_type std::allocator_traits< typename >::max_size (const _Alloc & __a) [inline], [static], [constexpr], [noexcept]

The maximum supported allocation size.

Parameters
    __a An allocator.

Returns
    __a.max_size() or numeric_limits<size_type>::max()

Returns __a.max_size() if that expression is well-formed, otherwise returns numeric_limits<size_type>::max()

  template<typename > static constexpr _Alloc std::allocator_traits< typename >::select_on_container_copy_construction (const _Alloc & __rhs) [inline], [static], [constexpr]

Obtain an allocator to use when copying a container.

Parameters
    __rhs An allocator.

Returns
    __rhs.select_on_container_copy_construction() or __rhs

Returns __rhs.select_on_container_copy_construction() if that expression is well-formed, otherwise returns __rhs

Author

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