std::indirect<T, Allocator>::operator->, std::indirect<T, Allocator>::operator*

 

C++

编译器支持

自立实现与有宿主实现

语言

标准库

标准库标头

具名要求

功能特性测试宏 (C++20)

语言支持库

概念库 (C++20)

诊断库

内存管理库

元编程库 (C++11)

通用工具库

容器库

迭代器库

范围库 (C++20)

算法库

字符串库

文本处理库

数值库

日期和时间库

输入/输出库

文件系统库 (C++17)

并发支持库 (C++11)

执行控制库 (C++26)

技术规范

符号索引

外部库

 

内存管理库

voidify (仅用于阐述*) 分配器 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) 未初始化内存算法 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) 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::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) 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::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) 显式生存期管理 start_lifetime_as (C++23) start_lifetime_as_array (C++23) 用于复合类设计的类型 indirect (C++26) polymorphic (C++26) 未初始化存储 (C++20 前) raw_storage_iterator (C++17 弃用) get_temporary_buffer (C++17 弃用) return_temporary_buffer (C++17 弃用) 垃圾收集器支持 (C++23 前) declare_reachable (C++11)(C++23 前) declare_no_pointers (C++11)(C++23 前) pointer_safety (C++11)(C++23 前) undeclare_reachable (C++11)(C++23 前) undeclare_no_pointers (C++11)(C++23 前) get_pointer_safety (C++11)(C++23 前)

低层内存管理 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) 智能指针 unique_ptr (C++11) shared_ptr (C++11) weak_ptr (C++11) auto_ptr (C++17 前*) 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) 杂项 pointer_traits (C++11) to_address (C++20) addressof (C++11) align (C++11) assume_aligned (C++20) is_sufficiently_aligned (C++26) C 库 malloc calloc realloc free aligned_alloc (C++17)

 

std::indirect

成员函数

indirect::indirect

indirect::~indirect

indirect::operator=

观察器

indirect::operator->indirect::operator*

indirect::valueless_after_move

indirect::get_allocator

修改器

indirect::swap

非成员函数

operator==operator<=>

swap(std::indirect)

推导指引

辅助类

hash<std::indirect>

 

constexpr const_pointer operator->() const noexcept;	(1)	(C++26 起)
constexpr pointer operator->() noexcept;	(2)	(C++26 起)
constexpr const T& operator*() const& noexcept;	(3)	(C++26 起)
constexpr T& operator*() & noexcept;	(4)	(C++26 起)
constexpr const T&& operator*() const&& noexcept;	(5)	(C++26 起)
constexpr T&& operator*() && noexcept;	(6)	(C++26 起)

访问拥有的值。

1,2) 返回指向拥有的值的指针。

3-6) 返回到拥有的值的引用。

如果 *this 无值，那么行为未定义。

返回值

1,2) p

3,4) *p

5,6) std::move(*p )

注解

此运算符不检查 *this 是否无值，用户可以手动用 valueless_after_move() 做检查。