C++ passing private data to other private functions in a class

Question

I'm not having any trouble accessing my private data within member functions but I am having trouble passing the data to another function within the class. I am relatively new to c++ and I am wondering if I was making some sort of blunderous error. I wanted to set up four public functions to be called from outside the class, and have those functions pass in the correct private data member to a private function within class for execution. I thought this would be good promote code reuse but it doesn't seem to let me do this. Any help would be appreciated.

Header:

class CoaxGage 
{
  public:
    CoaxGage();
    ~CoaxGage();
    bool reconnect();
    bool is_connected();
    bool disconnect();
    bool get_storage_data();
    void async_get_storage_data(void);
    std::pair<bool,bool> async_get_check_done(void);
    bool start_data_storage(void);
    void async_start_data_storage(void);
    std::pair<bool,bool> async_start_check_done(void);
    bool stop_data_storage(void);
    void async_stop_data_storage(void);
    std::pair<bool,bool> async_stop_check_done(void);
    bool clear_storage_data(void);
    void async_clear_storage_data(void);
    std::pair<bool,bool> async_clear_check_done(void);
  private:
    std::pair<bool,bool> async_check_done_(std::future<bool> fut);
    bool connect_();
    bool connected_;
    bool get_storage_count_(DWORD &count);
    std::vector<FLOAT> values_;
    void parse_data_elements_(LS9IF_STORAGE_DATA *data_array, int size);
    std::future<bool> get_future_;
    std::future<bool> start_future_;
    std::future<bool> stop_future_;
    std::future<bool> clear_future_;
};

Function passing the data:

std::pair<bool,bool> CoaxGage::async_clear_check_done(void)
{
    return async_check_done_(clear_future_);
}

Function receiving the data:

std::pair<bool,bool> CoaxGage::async_check_done_(std::future<bool> fut)
{
    bool done, ret = false;
    auto status = fut.wait_for(std::chrono::milliseconds(0));

    if (status == std::future_status::ready) 
    {
        done = true;
        ret = clear_future_.get();
    } 
    return std::make_pair(done, ret);
}

Error:

• error C2248: 'std::future<_Ty>::future' : cannot access private member declared in class 'std::future<_Ty>'