std::allocator_traits - Man Page
Uniform interface to all allocator types.
Synopsis
#include <memory>
Inherits __allocator_traits_base.
Inherited by __gnu_cxx::__alloc_traits< _Tp_alloc_type >, and __gnu_cxx::__alloc_traits< _Alloc, typename >.
Public Types
typedef _Alloc allocator_type
The allocator type.
using const_pointer = typename _Ptr< __c_pointer, const value_type >::type
The allocator's const pointer type.
using const_void_pointer = typename _Ptr< __cv_pointer, const void >::type
The allocator's const void pointer type.
using difference_type = typename _Diff< _Alloc, pointer >::type
The allocator's difference type.
using is_always_equal = typename __detected_or_t< is_empty< _Alloc >, __equal, _Alloc >::type
Whether all instances of the allocator type compare equal.
using pointer = __detected_or_t< value_type *, __pointer, _Alloc >
The allocator's pointer type.
using propagate_on_container_copy_assignment = __detected_or_t< false_type, __pocca, _Alloc >
How the allocator is propagated on copy assignment.
using propagate_on_container_move_assignment = __detected_or_t< false_type, __pocma, _Alloc >
How the allocator is propagated on move assignment.
using propagate_on_container_swap = __detected_or_t< false_type, __pocs, _Alloc >
How the allocator is propagated on swap.
template<typename _Tp > using rebind_alloc = __alloc_rebind< _Alloc, _Tp >
template<typename _Tp > using rebind_traits = allocator_traits< rebind_alloc< _Tp > >
using size_type = typename _Size< _Alloc, difference_type >::type
The allocator's size type.
typedef _Alloc::value_type value_type
The allocated type.
using void_pointer = typename _Ptr< __v_pointer, void >::type
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> static constexpr auto construct (_Alloc &__a, _Tp *__p, _Args &&... __args) noexcept(noexcept(_S_construct(__a, __p, std::forward< _Args >(__args)...))) -> decltype(_S_construct(__a, __p, std::forward< _Args >(__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(noexcept(_S_destroy(__a, __p, 0)))
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 _Alloc>
struct std::allocator_traits< _Alloc >"Uniform interface to all allocator types.
- Since
C++11
Member Typedef Documentation
template<typename _Alloc > typedef _Alloc std::allocator_traits< _Alloc >::allocator_type
The allocator type.
template<typename _Alloc > using std::allocator_traits< _Alloc >::const_pointer = typename _Ptr<__c_pointer, const value_type>::type
The allocator's const pointer type. Alloc::const_pointer
if that type exists, otherwise pointer_traits<pointer>::rebind<const value_type>
template<typename _Alloc > using std::allocator_traits< _Alloc >::const_void_pointer = typename _Ptr<__cv_pointer, const void>::type
The allocator's const void pointer type. Alloc::const_void_pointer
if that type exists, otherwise pointer_traits<pointer>::rebind<const void>
template<typename _Alloc > using std::allocator_traits< _Alloc >::difference_type = typename _Diff<_Alloc, pointer>::type
The allocator's difference type. Alloc::difference_type
if that type exists, otherwise pointer_traits<pointer>::difference_type
template<typename _Alloc > using std::allocator_traits< _Alloc >::is_always_equal = typename __detected_or_t<is_empty<_Alloc>, __equal, _Alloc>::type
Whether all instances of the allocator type compare equal. Alloc::is_always_equal
if that type exists, otherwise is_empty<Alloc>::type
template<typename _Alloc > using std::allocator_traits< _Alloc >::pointer = __detected_or_t<value_type*, __pointer, _Alloc>
The allocator's pointer type. Alloc::pointer
if that type exists, otherwise value_type*
template<typename _Alloc > using std::allocator_traits< _Alloc >::propagate_on_container_copy_assignment = __detected_or_t<false_type, __pocca, _Alloc>
How the allocator is propagated on copy assignment. Alloc::propagate_on_container_copy_assignment
if that type exists, otherwise false_type
template<typename _Alloc > using std::allocator_traits< _Alloc >::propagate_on_container_move_assignment = __detected_or_t<false_type, __pocma, _Alloc>
How the allocator is propagated on move assignment. Alloc::propagate_on_container_move_assignment
if that type exists, otherwise false_type
template<typename _Alloc > using std::allocator_traits< _Alloc >::propagate_on_container_swap = __detected_or_t<false_type, __pocs, _Alloc>
How the allocator is propagated on swap. Alloc::propagate_on_container_swap
if that type exists, otherwise false_type
template<typename _Alloc > using std::allocator_traits< _Alloc >::size_type = typename _Size<_Alloc, difference_type>::type
The allocator's size type. Alloc::size_type
if that type exists, otherwise make_unsigned<difference_type>::type
template<typename _Alloc > typedef _Alloc::value_type std::allocator_traits< _Alloc >::value_type
The allocated type.
template<typename _Alloc > using std::allocator_traits< _Alloc >::void_pointer = typename _Ptr<__v_pointer, void>::type
The allocator's void pointer type. Alloc::void_pointer
if that type exists, otherwise pointer_traits<pointer>::rebind<void>
Member Function Documentation
template<typename _Alloc > static constexpr pointer std::allocator_traits< _Alloc >::allocate (_Alloc & __a, size_type __n) [inline], [static], [constexpr]
Allocate memory.
Parameters
__a An allocator.
__n The number of objects to allocate space for.
Calls a.allocate(n)
template<typename _Alloc > static constexpr pointer std::allocator_traits< _Alloc >::allocate (_Alloc & __a, size_type __n, const_void_pointer __hint) [inline], [static], [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 _Alloc > template<typename _Tp , typename... _Args> static constexpr auto std::allocator_traits< _Alloc >::construct (_Alloc & __a, _Tp * __p, _Args &&... __args) -> decltype(_S_construct(__a, __p, std::forward<_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...
template<typename _Alloc > static constexpr void std::allocator_traits< _Alloc >::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 _Alloc > template<typename _Tp > static constexpr void std::allocator_traits< _Alloc >::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()
template<typename _Alloc > static constexpr size_type std::allocator_traits< _Alloc >::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 _Alloc > static constexpr _Alloc std::allocator_traits< _Alloc >::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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