std::weak_ptr 的推导指引

 

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voidify (仅为说明目的*) 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) 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) C 语言库 malloc calloc realloc aligned_alloc (C++17) free

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std::weak_ptr

成员函数

weak_ptr::weak_ptr

weak_ptr::~weak_ptr

weak_ptr::operator=

修改器

weak_ptr::reset

weak_ptr::swap

观察器

weak_ptr::use_count

weak_ptr::expired

weak_ptr::lock

weak_ptr::owner_before

weak_ptr::owner_hash (C++26)

weak_ptr::owner_equal (C++26)

非成员函数

swap(std::weak_ptr)

辅助类

atomic<std::weak_ptr> (C++20)

推导指引(C++17)

 

定义于头文件 <memory>
template< class T > weak_ptr( std::shared_ptr<T> ) -> weak_ptr<T>;		(自 C++17 起)

为 std::weak_ptr 提供了一个推导指引，以处理隐式推导指引遗漏的边缘情况。

示例

运行此代码

#include <memory>
 
int main()
{
    auto p = std::make_shared<int>(42);
    std::weak_ptr w{p}; // explicit deduction guide is used in this case
}