std::shared_ptr 是C++11 标准库中的智能指针类型,用于管理动态分配的对象。与传统指针不同,std::shared_ptr 自动管理内存,并在不再使用时自动释放对象,以避免内存泄漏。它是一种共享所有权的智能指针,即可以让多个 std::shared_ptr 指向同一个对象,并且会记录有多少个 std::shared_ptr 拥有该对象。 使用方法...
shared_ptr<void> spv(new int(1)); shared_ptr<int> spe(static_cast<int*>(spv.get())); shared_ptr<int> spn = static_pointer_cast<int>(spv); cout << *spe << endl; cout << *spn << endl; return 0; } 共享指针存在的问题 ①循环引用 ②明确想要共享但不拥有对象...
应用static_cast、dynamic_cast、const_cast或reinterpret_cast到被存储指针 (函数模板) get_deleter 返回指定类型中的删除器,若其拥有 (函数模板) operator==operator!=operator<operator<=operator>operator>=operator<=> (C++20 移除)(C++20 移除)(C++20 移除)(C++20 移除)(C++20 移除)(C++20) ...
这行代码尝试将 basePtr 转换为 std::shared_ptr<Derived>。dynamic_pointer_cast 会在运行时检查转换是否安全(即 basePtr 是否确实指向一个 Derived 类对象)。如果转换成功,derivedPtr 将被赋予新的类型,并指向原来的对象;如果转换失败,derivedPtr 将为nullptr。 检查转换结果并调用方法: cpp if (derived...
reinterpret_cast也不做任何事情。std::string::c_str()已经返回了一个const char*。reinterpret_cast只...
template<class...Args>voidforward(Args&&...args){f(std::forward<Args>(args)...);}template<classT>constexprT&&forward(std::remove_reference_t<T>&arg)noexcept{// forward an lvalue as either an lvalue or an rvaluereturn(static_cast<T&&>(arg));}template<classT>constexprT&&forward(std...
static_pointer_castdynamic_pointer_castconst_pointer_castreinterpret_pointer_cast (C++17) 应用static_cast、dynamic_cast、const_cast 或reinterpret_cast 到被存储指针 (函数模板) get_deleter 返回指定类型中的删除器,若其拥有 (函数模板) operator==operator!=operator<operator<=operator>operator>=operator...
shared_ptr<T> dynamic_pointer_cast(const shared_ptr<U>& r); 话虽如此,您可以像下面这样调用它: spBase base = std::make_shared<TestDerived>(); spDerived derived = std::dynamic_pointer_cast<spDerived::element_type>(base); // or: ...
~CustomAllocator() =default;template<typenameU>CustomAllocator(constCustomAllocator<U>&)noexcept{}T*allocate(size_tn){returnstatic_cast<T*>(MemoryPoolManager::GetInstance().Alloc(n *sizeof(T))); }voiddeallocate(T* p,size_t){ MemoryPoolManager::GetInstance().Free(p); ...
(*this,const_cast<std::remove_cv_t<U>*>(ptr));. The assignment to theweak_thisis not atomic and conflicts with any potentially concurrent access to the same object. This ensures that future calls toshared_from_this()would share ownership with thestd::shared_ptrcreated by this raw pointe...