Undefined reference to static member variable from within a static member function

Thanks so much for the help. What I have found is that I can’t really declare the static member as part of the StaticHelper class at all. If I do what you’ve suggested, I get an error on the StaticHelper:: part of the declaration in the .cpp file. If I remove that part and just make Test a static variable, it does work, however, now the variable is public and anyone can change it. It’s not clear to me that you can create a static member variable that is truly private to a class. I am able to move on at this point. Thanks again.