Question

我试图制作一个可变参数模板类postOffice

template <class... AllInputTypes>
class PostOffice {
public:
   PostOffice(AllInputTypes&... akkUboytTypes)
   : allInputMsgStorage(allInputTypes...) {}
...
protected:
   std::tuple<StorageSlot<AllInputTypes>...> allInputMsgStorage; //TODO: Will this work?
}

使用StorageSlot

template<class InputMsgType>
class StorageSlot {
public:
    StorageSlot(InputMsgType& input)
    : readFlag(false),
      writeFlag(false),
      storageField(input)
      //TODO initialize timer with period, get period from CAN
    {}
    virtual ~StorageSlot();
    InputMsgType storageField; //the field that it is being stored into
    bool readFlag; //the flag that checks if it is being read into
    bool writeFlag; //flag that checks if it is being written into
    Timer StorageSlotTimer; //the timer that checks the read and write flag
};

所以在元组中，我试图初始化一个元组

StorageSlot<AllInputType1>, StorageSlot<AllInputType2>,...

等

这会有用吗？我试过了

std::tuple<StorageSlot<AllInputTypes...>> allInputMsgStorage;

但是这会在可变参数模板和单个模板存储槽之间产生不匹配。但是，我不确定IF

std::tuple<StorageSlot<AllInputTypes>...> allInputMsgStorage;

是根本定义的（StorageSlot不是模板），更不用说产生正确的结果了。我能想到这项工作的唯一原因是让StorageSlot<AllInputTypes>直接发送到postOffice，然后执行

std::tuple<AllInputTypeStorageSlots...> allInputMsgStorage;

使PostOffice类的模板接口有点丑陋

这样做会有效，如果没有，我怎么能让它发挥作用呢？

Answer 1

一般概念是正确的 - 稍微改进一下，构造函数可以得到完美的转发以提高效率。

此外，StorageSlot中不需要虚拟析构函数 - 除非您要使用动态多态，否则始终使用零规则：

可编辑的代码：

#include <tuple>
#include <string>

struct Timer
{};

template<class InputMsgType>
class StorageSlot {
public:

    template<class ArgType>
    StorageSlot(ArgType&& input)
        : readFlag(false),
        writeFlag(false),
        storageField(std::forward<ArgType>(input))
    //TODO initialize timer with period, get period from CAN
    {}

    InputMsgType storageField; //the field that it is being stored into
    bool readFlag; //the flag that checks if it is being read into
    bool writeFlag; //flag that checks if it is being written into
    Timer StorageSlotTimer; //the timer that checks the read and write flag
};


template <class... AllInputTypes>
class PostOffice {
public:

    //
    // note - perfect forwarding
    //
    template<class...Args>
    PostOffice(Args&&... allInputTypes)
    : allInputMsgStorage(std::forward<Args>(allInputTypes)...)
    {

    }

protected:
    std::tuple<StorageSlot<AllInputTypes>...> allInputMsgStorage; //TODO: Will this work? - yes
};





int main()
{
    PostOffice<int, double, std::string> po(10, 20.1, "foo");

}

使用variadic模板创建模板类元组

1 个答案: