C / C++ / MFC

typedef int (CMyClass::* LPFNMYCLASSMEMBER)(long, void*);
...

//your function prototype:
bool YourFunction(LPFNMYCLASSMEMBER pfnMember)
{
   ...
   // get a pointer to the object on which you will call pfnMember
   CMyClass* pClass = something;
   // make the call
   int iRetVal = pClass->*pfnMember(aLongParam, aVoidPtrParam);
   ...
}

class CTestClass
{
   public:
      int ANonStaticMember(void* pData);
      static int AStaticMember(void* pData);

      CString m_csNonStaticData;
      static CString m_csStaticData;
}

CString CTestClass::m_csStaticData = ""; // initialization of static data

int CTestClass::ANonStaticMember (void* pData)
{
   // here we can access non-static data member
   m_csNonStaticData = *(CString*)pData;
   // and we can access static data member
   m_csStaticData = *(CString*)pData;
}

int CTestClass::AStaticMember (void* pData)
{
   // here we can only access static data member
   m_csStaticData = *(CString*)pData;
   // it would be an error to access the non-static member
}

void Foo()
{
   // call SetTimer with static member function as callback is OK
   SetTimer(NULL, 1000, &CTestClass::AStaticMember);
   // calll SetTimer with non-static member as callback is error
   SetTimer(NULL, 1000, &CTetsClass::ANonStaticMember); // ERROR
}