本文基于项目实战介绍了C++11智能指针的类型转换std::dynamic_pointer_cast，以及特殊的智能指针std::shar...
From the record-playback GitHub README, it says "In order to allow using different types of devices (rs2::recorder, rs2::playback) and read\write to the same file, we define a shared pointer to rs2::pipeline. This way we'll be able to release previous resources when switching to a...
and returns an object of typeshared_ptr<T>that owns and stores a pointer to it (with ause c...
make_shared为构造动作提供了更加简明的表达。由于它将shared_ptr的计数置于对象之后,使用它还可以提供减少另外一次的增加计数的机会。 Example(示例) 代码语言:javascript 代码运行次数:0 voidtest(){// OK: but repetitive; and separate allocations for the Bar and shared_ptr's use countshared_ptr<Bar>p{n...
它们的区别在于 make_shared 只有一次内存申请操作,而 shared_ptr 构造函数会有两次。 shared_ptr 对象会管理两部分内容, 控制块,比如引用计数、deleter 等等 要被管理的对象 当调用 make_shared 的时候,会申请一份足够大的内存同时给控制块和对象使用。而 shared_ptr 构造函数会分别为控制块和对象调用内存申请,详...
3.因此,当内存紧张且托管对象非常大时,如果weak_ptr的生命期比shared_ptr更长时,不建议使用make_shared。 【编程实验】make系列函数的优劣 #include <iostream>#include<memory>//for smart pointer#include <vector>usingnamespacestd;classWidget {public: ...
3.因此,当内存紧张且托管对象非常大时,如果weak_ptr的生命期比shared_ptr更长时,不建议使用make_shared。 【编程实验】make系列函数的优劣 #include <iostream>#include<memory>//for smart pointer#include <vector>usingnamespacestd;classWidget {public: ...
事实并非如此,因为shared_ptr是一个临时对象。 您在这里遇到的正是weak_ptr的构建目的——只有在其他一些shared_ptr指向同一个底层对象时它才有效。那是its purpose: std::weak_ptr is a smart pointer that holds a non-owning ("weak") reference to an object that is managed by std::shared_ptr... ...
These functions may be used as an alternative tostd::shared_ptr<T>(new T(args...)). The trade-offs are: std::shared_ptr<T>(new T(args...))performs at least two allocations (one for the objectTand one for the control block of the shared pointer), whilestd::make_shared<T>typica...
autoremaining =QSharedPointer<int>::create(count); autoresults =QSharedPointer<QVector<T>>::create(count); inti =0; for(constauto& promise: promises) { Expand DownExpand Up@@ -94,7 +94,7 @@ all(const Sequence<QPromise<void>, Args...>& promises) ...