c++ - 如何在我的模板类中初始化这个静态类变量？

Question

我有以下代码(it's on ideone.com):

template<class T>
class CMemoryPool
{
public:
    CMemoryPool(int param1)
        : stuff(param1)
    {}

private:
    T stuff;
};

template<class T>
class CList
{
public:
    struct Entry
    {
        T data;
    };

    static CMemoryPool<Entry> s_pool;
};

template<class T>
CList<T>::CMemoryPool<CList<T>::Entry>::s_pool(1);

int main()
{
    CList<int> list;
}

我似乎无法在要编译的类之外获取s_pool 的初始化。谁能帮我弄清楚如何进行这项工作？请注意，我仅使用 C++03。

Answer 1

我认为您忘记了初始化静态数据成员的一般工作方式:

struct Data { int i; };

struct Holder { static Data StaticMember; };

Data Holder::StaticMember = { 1 };
^    ^~~~~~~~~~~~~~~~~~~~ static member qualified name
\~~~ static member type

如果您查看您的声明，您会发现您忘记了上述两项之一:

// Only a single element: there should be a type and a name
template<class T>
CList<T>::template CMemoryPool<typename CList<T>::Entry>::s_pool(1);

// Two elements
template<class T>
CMemoryPool<typename CList<T>::Entry> CList<T>::s_pool(1);
^                                     ^~~~~~~~~~~~~~~~ name
 \~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ type

一旦更正it just works