std::allocator_traits<Alloc>::select_on_container_copy_construction

 

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未初始化内存算法 uninitialized_copy uninitialized_fill uninitialized_move (C++17) uninitialized_default_construct (C++17) uninitialized_value_construct (C++17) destroy (C++17) destroy_at (C++17) voidify (C++20) 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) construct_at (C++20) 受约束的未初始化内存算法 ranges::uninitialized_copy (C++20) ranges::uninitialized_fill (C++20) ranges::uninitialized_move (C++20) ranges::construct_at (C++20) ranges::destroy (C++20) ranges::destroy_n (C++20) ranges::destroy_at (C++20) ranges::uninitialized_copy_n (C++20) ranges::uninitialized_fill_n (C++20) ranges::uninitialized_move_n (C++20) ranges::uninitialized_default_construct (C++20) ranges::uninitialized_value_construct (C++20) ranges::uninitialized_default_construct_n (C++20)   ranges::uninitialized_value_construct_n (C++20) 分配器 allocator allocator_traits (C++11) allocation_result (C++23) 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) 内存资源 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) 垃圾收集支持 declare_reachable (C++11)(C++23 前) undeclare_reachable (C++11)(C++23 前) declare_no_pointers (C++11)(C++23 前) undeclare_no_pointers (C++11)(C++23 前) pointer_safety (C++11)(C++23 前) get_pointer_safety (C++11)(C++23 前) 未初始化存储 raw_storage_iterator (C++20 前*) get_temporary_buffer (C++20 前*) return_temporary_buffer (C++20 前*) 显式生存期管理 start_lifetime_asstart_lifetime_as_array (C++23)(C++23)

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std::allocator_traits

成员函数

allocator_traits::allocate (C++11)

allocator_traits::allocate_at_least (C++23)

allocator_traits::deallocate (C++11)

allocator_traits::construct (C++11)

allocator_traits::destroy (C++11)

allocator_traits::max_size (C++11)

allocator_traits::select_on_container_copy_construction (C++11)

 

在标头 <memory> 定义
static Alloc select_on_container_copy_construction( const Alloc& a );		(C++11 起) (C++20 前)
static constexpr Alloc select_on_container_copy_construction( const Alloc& a );		(C++20 起)

若可能，则获得分配器 a 的赋值构造函数版本，通过调用 a.select_on_container_copy_construction() 。若上述不可行（例如 Alloc 无成员函数 select_on_container_copy_construction() ），则返回不修改的 a 。

此函数为所有标准库容器的复制构造函数所调用。它允许构造函数参数所用的分配器为正在复制的容器所具备，并在需要的情况下修改状态。

参数

a

-

标准容器用以传递给容器复制构造函数的分配器

返回值

复制构造的标准容器所用的分配器。

参阅

select_on_container_copy_construction

复制 scoped_allocator_adaptor 与其所有分配器的状态 (std::scoped_allocator_adaptor<OuterAlloc,InnerAlloc...> 的公开成员函数)