在不知道其声明签名的情况下将任意函数对象存储到类成员容器中 [英] Storing arbitrary function objects into a class member container without knowing their declaration signature

问题描述

我有一个类模板，我不知道是否需要将 class Func 作为其参数之一。我也不知道是否可以将 std :: function 直接存储到没有模板参数列表的容器中。我的班级看起来像这样：

I have a class template, and I do not know if I need to have as one of its arguments class Func or not. I also do not know if I can arbitrarily store a std::function directly into a container without its template argument parameter list. My class looks something like:

template<class Data, class Func>
class ThreadManager final {
private:
    std::vector<std::shared_ptr<Data>> storedDataPtrs;
    std::vector<std::shared_ptr<std::thread>> storedThreadPtrs;

    // Is this valid? I know that `std::function is a class template wrapper 
    // that depends on template argument types. However I do not know
    // what kind of func will be stored...
    std::vector<std::shared_ptr<std::function>> storedFunctionPtrs;

public:
    ThreadManager() = default;
    ~ThreadManager() = default; // will change to clean up containers.
    ThreadManager( const ThreadManager & c ) = delete;
    ThreadManager& operator=( const ThreadManager & c ) = delete;        
};

当我去编写将添加数据，线程和函数对象的函数时，类似{ code>函数对象，函数指针， lambda ， std :: function< ...> }是否可以类似地声明 function 的参数？

Also similar when I go to write the function that will add the data, thread and function object {function object, function pointer, lambda, std::function<...>} Would I be able to declare the parameter for the function similarly?

还是我应该只使用实际的模板参数本身？

Or should I just use the actual template argument itself?

 std::vector<std::shared_ptr<Func>> storedFuncPtrs;

如果第二种情况是首选方式，那么我将如何实际存储 func obj ？是首选 std :: forward 还是 std :: move ？添加对象的方法是否应声明为 Func&& func ？

And if the second case here is the preferred way, then how would I go about to actually store the func obj? Would std::forward or std::move be preferred? Should the method to add in the objects be declared as Func&& func?

我想尽可能保持此类的通用性，模块化和可移植性，同时努力保持最佳的现代c ++ 17

I'd like to keep this class as generic, modular and portable as possible while trying to maintain modern c++17 best practices.

编辑

在听完用户Liliscent的建议后，我认为这就是她在整个评论中所说的。

After listening to user Liliscent's advice I think this is what she was stating throughout the comments.

std::vector<std::function<Func>>  _storedFuncObjs;

推荐答案

为什么该类存储 std :: thread s 和 数据 s 和 Func s？

Why is this class storing std::threads and Datas and Funcs?

这些线程的可调用对象是什么？

What Callable are you starting those threads with?

• Func 的实例已应用于 Data ？
  
  
  
  
  • 您只需要线程 s。
  
  
  • Instances of Func applied to Data?
    • You only need the threads.
    
    
    • 存储 std :: future< Data> s（可能还有 thread ，具体取决于您如何创建期货）
    
    
    • Store std::future<Data>s (and possibly threads, depending on how you create the futures)
    
    
    • 存储 std :: packaged_task< Data（Args ...）> 并分发 std :: future< Data> 是创建的那些。
    
    
    • Store std::packaged_task<Data(Args...)> and hand out the std::future<Data>s those created.

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