swap(C++ 标准库)
交换两 shared_ptr 或 weak_ptr 对象。
template<class Ty, class Other>
void swap(shared_ptr<Ty>& left, shared_ptr<Other>& right);
template<class Ty, class Other>
void swap(weak_ptr<Ty>& left, weak_ptr<Other>& right);
参数
Ty
左/共享弱指针控制的类型。Other
权限控制的类型/共享弱指针。left
左/共享弱指针。right
向右/共享弱指针。
备注
模板还调用名为 left.swap(right)的函数。
示例
// std_tr1__memory__swap.cpp
// compile with: /EHsc
#include <memory>
#include <iostream>
struct deleter
{
void operator()(int *p)
{
delete p;
}
};
int main()
{
std::shared_ptr<int> sp1(new int(5));
std::shared_ptr<int> sp2(new int(10));
std::cout << "*sp1 == " << *sp1 << std::endl;
sp1.swap(sp2);
std::cout << "*sp1 == " << *sp1 << std::endl;
swap(sp1, sp2);
std::cout << "*sp1 == " << *sp1 << std::endl;
std::cout << std::endl;
std::weak_ptr<int> wp1(sp1);
std::weak_ptr<int> wp2(sp2);
std::cout << "*wp1 == " << *wp1.lock() << std::endl;
wp1.swap(wp2);
std::cout << "*wp1 == " << *wp1.lock() << std::endl;
swap(wp1, wp2);
std::cout << "*wp1 == " << *wp1.lock() << std::endl;
return (0);
}
要求
页眉: <内存>
命名空间: std