ScopeGuard

class ScopeGuard{public:    explicit ScopeGuard(std::function<void()> onExitScope)        : onExitScope_(onExitScope), dismissed_(false)    { }    ~ScopeGuard()    {        if(!dismissed_)        {            onExitScope_();        }    }    void Dismiss()    {        dismissed_ = true;    }private:    std::function<void()> onExitScope_;    bool dismissed_;private: // noncopyable    ScopeGuard(ScopeGuard const&);    ScopeGuard& operator=(ScopeGuard const&);};

这个类的使用很简单，你交给它一个std::function，它负责在析构的时候执行，绝大多数时候这个function就是lambda，例如：

HANDLE h = CreateFile(...);ScopeGuard onExit([&] { CloseHandle(h); });class ScopeGuard{public:    explicit ScopeGuard(std::function<void()> onExitScope)        : onExitScope_(onExitScope), dismissed_(false)    { }    ~ScopeGuard()    {        if(!dismissed_)        {            onExitScope_();        }    }    void Dismiss()    {        dismissed_ = true;    }private:    std::function<void()> onExitScope_;    bool dismissed_;private: // noncopyable    ScopeGuard(ScopeGuard const&);    ScopeGuard& operator=(ScopeGuard const&);};

这个类的使用很简单，你交给它一个std::function，它负责在析构的时候执行，绝大多数时候这个function就是lambda，例如：

HANDLE h = CreateFile(...);ScopeGuard onExit([&] { CloseHandle(h); });