1. 解释std::static_pointer_cast的基本概念 std::static_pointer_cast 是C++11 引入的一个模板函数,用于智能指针(如 std::shared_ptr 或std::weak_ptr)之间的类型转换。这种转换是编译时的强制转换,不会在运行时进行检查,类似于 static_cast,但专门用于智能指针,确保转换后的指针仍然保留智能指针的内存管理功能...
不用std::static_pointer_cast // static_pointer_cast example #include <iostream> #include <memory> struct A { static const char* static_type; const char* dynamic_type; A() { dynamic_type = static_type; } }; struct B: A { static const char* static_type; B() { dynamic_type = sta...
std::shared_ptr<T> static_pointer_cast( const std::shared_ptr<U>& r ) noexcept; (1) (C++11 起) template< class T, class U >std::shared_ptr<T> static_pointer_cast( std::shared_ptr<U>&& r ) noexcept; (2) (C++20 起) template< class T, class U >std::shared_ptr<T> ...
r-the pointer to convert Notes The expressionsstd::shared_ptr<T>(static_cast<T*>(r.get())),std::shared_ptr<T>(dynamic_cast<T*>(r.get()))andstd::shared_ptr<T>(const_cast<T*>(r.get()))might seem to have the same effect, but they all will likely result in undefined behavior...
调用右值重载(2,4,6,8)后,r为空且r.get()==nullptr,但对于dynamic_pointer_cast(4),若dynamic_cast失败则不修改r。 (C++20 起) 参数 r-要转换的指针 注解 表达式std::shared_ptr<T>(static_cast<T*>(r.get()))、std::shared_ptr<T>(dynamic_cast<T*>(r.get()))及std::shared_ptr<T>(con...
《C++面向对象程序设计》✍千处细节、万字总结（建议收藏）「建议收藏」
Let Y be typename std::experimental::shared_ptr<T>::element_type, then the resulting std::experimental::shared_ptr's stored pointer will be obtained by calling (in respective order): 1) static_cast<Y*>(r.get()).2) dynamic_cast<Y*>(r.get()) (if the result of the dynamic_cast ...