std::pmr::operator==, std::pmr::operator!=

 

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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)(直到 C++23) undeclare_reachable (C++11)(直到 C++23) declare_no_pointers (C++11)(直到 C++23) undeclare_no_pointers (C++11)(直到 C++23) pointer_safety (C++11)(直到 C++23) get_pointer_safety (C++11)(直到 C++23) 未初始化存储 raw_storage_iterator (直到 C++20*) get_temporary_buffer (直到 C++20*) return_temporary_buffer (直到 C++20*) 显式生命周期管理 start_lifetime_asstart_lifetime_as_array (C++23)(C++23)

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std::pmr::polymorphic_allocator

成员函数

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

非成员函数

operator==operator!= (直到 C++20)

 

在头文件 <memory_resource> 中定义
template< class T1, class T2 > bool operator==( const std::pmr::polymorphic_allocator<T1>& lhs,                  const std::pmr::polymorphic_allocator<T2>& rhs ) noexcept;	(1)	(自 C++17 起)
friend bool operator==( const polymorphic_allocator& lhs,                         const polymorphic_allocator& rhs ) noexcept;	(2)	(自 C++17 起)
template< class T1, class T2 > bool operator!=( const std::pmr::polymorphic_allocator<T1>& lhs,                  const std::pmr::polymorphic_allocator<T2>& rhs ) noexcept;	(3)	(自 C++17 起) (直到 C++20)
friend bool operator!=( const polymorphic_allocator& lhs,                         const polymorphic_allocator& rhs ) noexcept;	(4)	(自 C++17 起) (直到 C++20)

比较两个多态分配器。如果两个多态分配器的底层内存资源比较相等，则它们比较相等。

1) 返回 *lhs.resource() == *rhs.resource().

2) 与 (1) 相同，允许转换为 polymorphic_allocator。
此函数对普通的 无限定 或 限定查找 不可見，只有当 std::pmr::polymorphic_allocator 是参数的关联类时，才能通过 参数相关查找 找到它。

3) 返回 !(lhs == rhs).

4) 与 (3) 相同，允许转换为 polymorphic_allocator。
此函数对普通的 无限定 或 限定查找 不可見，只有当 std::pmr::polymorphic_allocator 是参数的关联类时，才能通过 参数相关查找 找到它。

!= 运算符是 从 operator== 合成的。

(自 C++20 起)

参数

lhs, rhs

-

要比较的多态分配器

返回值

1,2) *lhs.resource() == *rhs.resource()

3,4) !(lhs == rhs)

缺陷报告

以下更改行为的缺陷报告被追溯应用于先前发布的 C++ 标准。

DR	应用于	发布的行为	正确的行为
LWG 3683	C++17	polymorphic_allocator 无法与可转换为它的类型进行比较	添加重载