std::allocation_result

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Memory management library

voidify

(exposition only*)

Allocators

allocator
allocator_traits (C++11)
allocation_result (C++23)
scoped_allocator_adaptor (C++11)
pmr::polymorphic_allocator (C++17)

allocator_arg (C++11)
uses_allocator (C++11)
uses_allocator_construction_args (C++20)
make_obj_using_allocator (C++20)
uninitialized_construct_using_allocator (C++20)

Uninitialized memory algorithms

uninitialized_copy
uninitialized_fill
uninitialized_move (C++17)
uninitialized_copy_n (C++11)
uninitialized_fill_n
uninitialized_move_n (C++17)
construct_at (C++20)

uninitialized_default_construct (C++17)
uninitialized_value_construct (C++17)
destroy (C++17)
uninitialized_default_construct_n (C++17)
uninitialized_value_construct_n (C++17)
destroy_n (C++17)
destroy_at (C++17)

Constrained uninitialized memory algorithms

ranges::uninitialized_copy (C++20)
ranges::uninitialized_fill (C++20)
ranges::uninitialized_move (C++20)
ranges::uninitialized_copy_n (C++20)
ranges::uninitialized_fill_n (C++20)
ranges::uninitialized_move_n (C++20)
ranges::construct_at (C++20)

ranges::uninitialized_default_construct (C++20)
ranges::uninitialized_value_construct (C++20)
ranges::destroy (C++20)
ranges::uninitialized_default_construct_n (C++20)
ranges::uninitialized_value_construct_n (C++20)
ranges::destroy_n (C++20)
ranges::destroy_at (C++20)

Memory resources

pmr::memory_resource (C++17)
pmr::get_default_resource (C++17)
pmr::set_default_resource (C++17)
pmr::new_delete_resource (C++17)
pmr::pool_options (C++17)

pmr::null_memory_resource (C++17)
pmr::synchronized_pool_resource (C++17)
pmr::unsynchronized_pool_resource (C++17)
pmr::monotonic_buffer_resource (C++17)

Explicit lifetime management
start_lifetime_as (C++23)
start_lifetime_as_array (C++23)

Types for composite class design
indirect (C++26)
polymorphic (C++26)

Uninitialized storage(until C++20)

raw_storage_iterator (until C++20*)
get_temporary_buffer (until C++20*)

return_temporary_buffer (until C++20*)

Garbage collector support(until C++23)

declare_reachable (C++11)(until C++23)
declare_no_pointers (C++11)(until C++23)
pointer_safety (C++11)(until C++23)

undeclare_reachable (C++11)(until C++23)
undeclare_no_pointers (C++11)(until C++23)
get_pointer_safety (C++11)(until C++23)

Low level memory
management

operator newoperator new[]

operator deleteoperator delete[]

(C++11)

(C++11)

(C++17)

(C++20)

(C++17)

(C++11)

(C++11)

(C++11)

(until C++17*)

(C++11)

(C++17)

(C++26)

(C++26)

enable_shared_from_this

(C++11)

(C++11)

(C++11)

(C++23)

(C++23)

(C++11)

(C++20)

(C++11)

(C++11)

(C++20)

is_sufficiently_aligned

(C++26)

C Library

malloc
calloc
realloc

free
aligned_alloc (C++17)

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Defined in header`<memory>`
template<class Pointer,class SizeType=std::size_t> struct allocation_result;		(since C++23)

allocation_result specializations are returned from theallocate_at_least member function of appropriateAllocator types (e.g.std::allocator::allocate_at_least) andstd::allocator_traits::allocate_at_least.

Every specialization ofallocation_result has no base classes or declared members other thanptr andcount, thus it is suitable foraggregate initialization andstructured binding.

[edit]Template parameters

Pointer	-	typicallystd::allocator_traits<Alloc>::pointer, where`Alloc` is anAllocator type
SizeType	-	typicallystd::allocator_traits<Alloc>::size_type, where`Alloc` is anAllocator type

[edit]Data members

Member name	Definition
ptr	a pointer of type`Pointer` which is typically used for the address of the first element in the storage allocated by`allocate_at_least` (public member object)
count	a value of type`SizeType` which is typically used for the actual number of elements in the storage allocated by`allocate_at_least` (public member object)

[edit]Notes

Pointer andSizeType are a pointer to an object type andstd::make_unsigned_t<std::ptrdiff_t> (which is almost always same asstd::size_t) by default.

Feature-test macro	Value	Std	Feature
`__cpp_lib_allocate_at_least`	`202302L`	(C++23)	Size-feedback in the Allocator interface

[edit]Example

This section is incomplete
Reason: no example

[edit]See also

allocate_at_least (C++23)	allocates uninitialized storage at least as large as requested size (public member function of`std::allocator<T>`)[edit]
allocate_at_least [static](C++23)	allocates storage at least as large as the requested size via an allocator (public static member function of`std::allocator_traits<Alloc>`)[edit]