std::allocator_traits<Alloc>::construct

 

C++

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Technical Specifications

 

Dynamic memory management

Smart pointers unique_ptr (C++11) shared_ptr (C++11) weak_ptr (C++11) auto_ptr (until C++17) owner_less (C++11) enable_shared_from_this (C++11) bad_weak_ptr (C++11) default_delete (C++11) Allocators allocator allocator_traits (C++11) allocator_arg_t (C++11) 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) scoped_allocator_adaptor (C++11) pmr::polymorphic_allocator (C++17) 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::null_memory_resource (C++17) pmr::synchronized_pool_resource (C++17) pmr::unsynchronized_pool_resource (C++17) pmr::monotonic_buffer_resource (C++17) pmr::pool_options (C++17)

Uninitialized storage uninitialized_copy uninitialized_fill uninitialized_move (C++17) uninitialized_default_construct (C++17) uninitialized_value_construct (C++17) destroy (C++17) uninitialized_copy_n (C++11) uninitialized_fill_n uninitialized_move_n (C++17) uninitialized_default_construct_n (C++17) uninitialized_value_construct_n (C++17) destroy_n (C++17) destroy_at (C++17) raw_storage_iterator (until C++20) get_temporary_buffer (until C++20) return_temporary_buffer (until C++20) Garbage collection support declare_reachable (C++11) undeclare_reachable (C++11) declare_no_pointers (C++11) undeclare_no_pointers (C++11) pointer_safety (C++11) get_pointer_safety (C++11) Miscellaneous pointer_traits (C++11) to_address (C++20) addressof (C++11) align (C++11) assume_aligned (C++20) C Library malloc aligned_alloc (C++17) calloc realloc free Low level memory management

 

std::allocator_traits

Member functions

allocator_traits::allocate

allocator_traits::deallocate

allocator_traits::construct

allocator_traits::destroy

allocator_traits::max_size

allocator_traits::select_on_container_copy_construction

 

Defined in header <memory>
template< class T, class... Args > static void construct( Alloc& a, T* p, Args&&... args );		(since C++11)

If possible, constructs an object of type T in allocated uninitialized storage pointed to by p, by calling

a.construct(p, std::forward<Args>(args)...)

If the above is not possible (e.g. a does not have the member function construct(),), then calls placement-new as

::new (static_cast<void*>(p)) T(std::forward<Args>(args)...)

Parameters

a	-	allocator to use for construction
args...	-	the constructor arguments to pass to a.construct() or to placement-new

Return value

(none)

Notes

This function is used by the standard library containers when inserting, copying, or moving elements.

Because this function provides the automatic fall back to placement new, the member function construct() is an optional Allocator requirement since C++11.

See also

operator newoperator new[]	allocation functions (function)
construct (deprecated in C++17)(removed in C++20)	constructs an object in allocated storage (public member function of std::allocator<T>)