static CArray C MFC [duplicate]-CodePudding

I simply cannot seem to be able to make a static CArray and work with it.

Here's my code:

class WhiteBoard
{
public:

    static CArray<WhiteBoard, WhiteBoard> test;

    void tester()
    {
        test.Add(*this);
    }
};

And upon calling the tester method, I get an unresolved external symbol. Full error code is:

Severity    Code    Description Project File    Line    Suppression State
Error   LNK2001 unresolved external symbol "public: static class CArray<class WhiteBoard,class WhiteBoard> WhiteBoard::test" (?test@WhiteBoard@@2V?$CArray@VWhiteBoard@@V1@@@A) MFCApplication2 C:\Users\sw.eng\source\repos\MFCApplication2\MFCApplication2Dlg.obj 1

This is my first time working with CArray but I messed around with CArray of int and all worked alright.

Could it be that I'm trying to have a CArray of WhiteBoard inside of WhiteBoard? (I do need this functionality to keep track of all child objects made, which is why I do it)

Removing the static keyword makes everything run. But then it's not a static member, and I need it to be one.

Anyways, all help would be incredible and very much appreciated.

EDIT 1:

I've made another class which I called BoardBoss. WhiteBoard inherits BoardBoss. CArray is now of BoardBoss type. CArray<BoardBoss, BoardBoss> test;

The issue persists.

CodePudding user response：

Static class members need to be defined. As posted, the WhiteBoard class merely declares the identifier test. That makes the compiler happy, but the linker fails, because it cannot find the referenced symbol when it is used.

To fix this you need to add the following to a compilation unit:

CArray<WhiteBoard, WhiteBoard> Whiteboard::test;