Static pointer definition syntax

I am trying to a singleton mymap class. I have declared a private *pInstance pointer. I am having problems in defining the pInstance pointer. Somehow I am not getting the syntax right. Please help me define the pInstance pointer. I tried this definition

template<> assoc<string, string>::*pInstance;

Code:

template<class A, class B>
class myclass
{
public:
....

private:
  static myclass<A, B> *pInstance;

 myclass()
 {
      if(pInstance==NULL)
            pInstance = new myclass<A, B>;
  }


};


template<> assoc<string, string>::*pInstance; 
//this is giving errors during build

try.cpp

Code:

typedef myclass<string, string> StrStrMap;

int main()
{
   StrStrMap a;
    ....
}

 

Also, instead of using a pInstance pointer, I use a pInstance object
what will be the pInstance definition