std::unique_ptr 是一个轻量、快速、只能移动(move-only)的智能指针, 用于管理具有独占所有权的资源. 默认情况下, 资源销毁通过delete发生, 但可以指定自定义删除器. 有状态的自定义删除器和函数指针作为删除器会增加 std::unique_ptr 对象的大小. 将 std::unique_ptr 转换为 std::shared_ptr 很容易方便. ...
std::unique_ptr指针的拷贝是非法的,因为如果你可以拷贝一个std::unique_ptr,你就会得到两个std::unique_ptr,而这两个指针指向同一个地方并且都认为自己拥有指向对象的所有权。所以std::unique_ptr是一种move-only的类型。对于析构函数,一个非空的std::unique_ptr销毁自己的资源。默认的,资源的销毁是通过std::...
拷贝一个std::unique_ptr是不允许的,假如说真的可以允许拷贝std::unique_ptr,那么将会有两个std::unique_ptr指向同一块资源区域,每一个都认为它自己拥有且可以摧毁那块资源。因此,std::unique_ptr是一个move-only类型。当它面临析构时,一个非空的std::unique_ptr会摧毁它所拥有的资源。默认情况下,std::uniq...
As a move-only type,unique_ptr's assignment operator only acceptsrvaluesarguments (e.g. the result ofstd::make_uniqueor astd::move'dunique_ptrvariable). Example Run this code #include <iostream>#include <memory>structFoo{intid;Foo(intid):id(id){std::cout<<"Foo "<<id<<'\n';}~Foo...
May be you should write move semantics for a function or const std::unique_ptr<Resource>&? Then the function doesn't own your pointer void takeOwnership(std::unique_ptr<Resource>&& res) { if (res) std::cout << *res << '\n'; } Copy Because a function only uses a raw pointer,...
{...};std::unique_ptr<Impl,decltype(my_deleter)>w1(new Impl, my_deleter);std::unique_ptr<Impl>w2(new Impl);// default_deleter// w1的类型是 std::unique_ptr<Impl, lambda []void (Impl *p)->void>// w2的类型是 std::unique_ptr<Impl, std::default_delete<Impl>>w1 =std::move(w2...
inu. This constructor only participates in overload resolution ifstd::is_move_constructible<Deleter>::valueistrue. IfDeleteris not a reference type, requires that it is nothrow-MoveConstructible(ifDeleteris a reference,get_deleter()andu.get_deleter()after move construction reference the same value...
谈起C++，它被公认为最难学的编程语言之一，不仅语法知识点广泛，细节内容之多，学习难度和学习周期也长...
对shared_ptr来说，除了封装的raw_ptr外还要保存ref_cnt和weak_cnt，因此需要额外的存储空间保存，gcc...
unique_ptr has one and only one owner. That owner will delete the allocated memory when unique_ptr goes out of scope. unique_ptr can't be copied. It is move only. shared_ptr is where there is no one defined owner and can be copied. shared_ptr maintains a count of 'usage'. Every ...