模板单例中的使用"/>
C++友缘类friend在自动释放模板单例中的使用
以下为实现代码:
#pragma region 自动释放模板单例
template<typename T>
class CSingletonFree;
template<typename T>
class CSingleton
{
public:static T*GetInstance(){if (m_pInstance == nullptr){unique_lock<mutex> lg(m_mtx);if (m_pInstance == nullptr){m_pInstance = new T;//cout << "创建单列" << endl;m_AutoFree.Instance = &m_pInstance;}}return m_pInstance;}protected:CSingleton(){}virtual~CSingleton(){//cout << "释放单列" << endl;}
private:static T*m_pInstance;static mutex m_mtx;static CSingletonFree<T> m_AutoFree;CSingleton(const CSingleton&) {};CSingleton& operator=(const CSingleton&) {};
};template<typename T>
T*CSingleton<T>::m_pInstance = nullptr;
template<typename T>
mutex CSingleton<T>::m_mtx;
template<typename T>
CSingletonFree<T> CSingleton<T>::m_AutoFree;
//自动释放
template<typename T>
class CSingletonFree
{
public:T * * Instance = nullptr;~CSingletonFree(){//cout << "自动释放" << endl;if (Instance){if (*Instance){delete *Instance;*Instance = nullptr;}Instance = nullptr;}//cout << "释放结束" << endl;}
};
#pragma endregion
以下为使用案例:
//单列使用例子
class ExampleSingleton :public CSingleton<ExampleSingleton>
{
public:int *Num;~ExampleSingleton(){//cout << "释放ExampleSingleton" << endl;//释放代码if (Num){delete Num;Num = nullptr;}};
private:ExampleSingleton() {};//防止外部创建friend class CSingleton<ExampleSingleton>;};
调用时请注意:
int main()
{ExampleSingleton* instance = ExampleSingleton::GetInstance();instance->Num = new int(2333);cout << *(instance->Num) << endl;//delete instance;//有自动释放这样写会报错的哦CON_PAUSEreturn 0;
}
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C++友缘类friend在自动释放模板单例中的使用
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