std::weak_ptr是一种智能指针,它持有被std::shared_ptr管理的对象的非拥有性“弱”引用。在访问引用的对象前必须先转换为std::shared_ptr。 std::weak_ptr实现临时所有权:当某个对象只有存在时才需要被访问,且随时可能被他人删除时,可以使用std::weak_ptr来跟踪该对象,需要获得临时所有权时,将其转换为std::...
std::weak_ptr<T>::weak_ptr constexprweak_ptr()noexcept; (1)(since C++11) weak_ptr(constweak_ptr&r)noexcept; (2)(since C++11) template<classY> weak_ptr(constweak_ptr<Y>&r)noexcept; (2)(since C++11) template<classY> weak_ptr(conststd::shared_ptr<Y>&r)noexcept; ...
std::weak_ptris a smart pointer that holds a non-owning ("weak") reference to an object that is managed bystd::shared_ptr. It must be converted tostd::shared_ptrin order to access the referenced object. std::weak_ptrmodels temporary ownership: when an object needs to be accessed only...
#include <iostream> #include <memory> std::weak_ptr<int> gw; void f() { if (!gw.expired()) std::cout << "gw 有效\n"; else std::cout << "gw 已过期\n"; } int main() { { auto sp = std::make_shared<int>(42); gw = sp; f(); } f(); } 输出: gw 有效 gw 已...
weak_ptr std::shared_ptr<int> sp = std::make_shared<int>(42); std::weak_ptr<int> wp = sp; // 检查引用对象是否存在 if (auto locked = wp.lock()) { std::cout << *locked << std::endl; // 输出: 42 } else { std::cout << "对象已被销毁" << std::endl; } // 检查是...
weak_ptr std::shared_ptr<int> sp = std::make_shared<int>(42); std::weak_ptr<int> wp = sp; // 检查引用对象是否存在 if (auto locked = wp.lock()) { std::cout << *locked << std::endl; // 输出: 42 } else { std::cout << "对象已被销毁" << std::endl; } // 检查是...
We have never seen a program that could be expressed better in C95 than in C++ (and we don’t think such a program could exist – every construct in C95 has an obvious C++ equivalent). However, there still exist a few environments where the support for C++ is so weak that there is ...
The raw pointer is not deleted until all shared_ptr owners have gone out of scope or have otherwise given up ownership. The size is two pointers; one for the object and one for the shared control block that contains the reference count. weak_ptr Special-case smart pointer for use in ...
#include <booster/hold_ptr.h> #include <booster/noncopyable.h> Go to the source code of this file. Classes classbooster::shared_ptr< T > classbooster::weak_ptr< T > classbooster::log::message This class represents a single message that should be written to log.More... ...
其实C++里也是用类似的概念,如boost里的weak_ptr 最爱用java开发,最喜欢C++,矛盾啊 回复更多评论 #re: java里头居然还有SoftReference、WeakReference 和 PhantomReference 2008-07-10 16:10 |niming sj回复更多评论 #re: java里头居然还有SoftReference、WeakReference 和 PhantomReference 2008-12-11 09:23 |CleeSa...