std::pmr::polymorphic_allocator<T>::polymorphic_allocator

 

C++

Compiler support

Freestanding and hosted

Language

Standard library

Standard library headers

Named requirements

Feature test macros (C++20)

Language support library

Concepts library (C++20)

Diagnostics library

Memory management library

Metaprogramming library (C++11)

General utilities library

Containers library

Iterators library

Ranges library (C++20)

Algorithms library

Strings library

Text processing library

Numerics library

Date and time library

Input/output library

Filesystem library (C++17)

Concurrency support library (C++11)

Execution control library (C++26)

Technical specifications

Symbols index

External libraries

 

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[] nothrow_t nothrow new_handler set_new_handler get_new_handler (C++11) bad_alloc bad_array_new_length (C++11) align_val_t (C++17) destroying_delete_t (C++20) launder (C++17) Smart pointers unique_ptr (C++11) shared_ptr (C++11) weak_ptr (C++11) auto_ptr (until C++17*) owner_less (C++11) owner_less<void> (C++17) owner_hash (C++26) owner_equal (C++26) enable_shared_from_this (C++11) bad_weak_ptr (C++11) default_delete (C++11) out_ptr_t (C++23) inout_ptr_t (C++23) Miscellaneous pointer_traits (C++11) to_address (C++20) addressof (C++11) align (C++11) assume_aligned (C++20) is_sufficiently_aligned (C++26) C Library malloc calloc realloc free aligned_alloc (C++17)

 

std::pmr::polymorphic_allocator

Member functions

polymorphic_allocator::polymorphic_allocator

polymorphic_allocator::allocate

polymorphic_allocator::deallocate

polymorphic_allocator::construct

polymorphic_allocator::destroy (C++20/26*)

polymorphic_allocator::allocate_bytes (C++20)

polymorphic_allocator::deallocate_bytes (C++20)

polymorphic_allocator::allocate_object (C++20)

polymorphic_allocator::deallocate_object (C++20)

polymorphic_allocator::new_object (C++20)

polymorphic_allocator::delete_object (C++20)

polymorphic_allocator::select_on_container_copy_construction

polymorphic_allocator::resource

Non-member functions

operator==operator!= (until C++20)

 

polymorphic_allocator() noexcept;	(1)
polymorphic_allocator( const polymorphic_allocator& other ) = default;	(2)
template< class U > polymorphic_allocator( const polymorphic_allocator<U>& other ) noexcept;	(3)
polymorphic_allocator( std::pmr::memory_resource* r );	(4)

Constructs a new polymorphic_allocator.

1) Constructs a polymorphic_allocator using the return value of std::pmr::get_default_resource() as the underlying memory resource.

2,3) Constructs a polymorphic_allocator using other.resource() as the underlying memory resource.

4) Constructs a polymorphic_allocator using r as the underlying memory resource. This constructor provides an implicit conversion from std::pmr::memory_resource*.

Parameters

other	-	another polymorphic_allocator to copy from
r	-	pointer to the memory resource to use. May not be null

Exceptions

4) Throws nothing.

Notes

Copying a container using a polymorphic_allocator will not call the allocator's copy constructor. Instead, the new container will use the return value of select_on_container_copy_construction (a default-constructed polymorphic_allocator) as its allocator.

See also

select_on_container_copy_construction

create a new polymorphic_allocator for use by a container's copy constructor (public member function)

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