no qualified name for pointer to member (found ':: *')
The pointer to member declaration did not specify a class.
The declaration of a pointer to a member of a class (or structure or union) must specify the name of the class.
The following is an example of this error:
class A {};
int ::* cp; // error, class not specifed
int B::* bp // error, B not defined
int A::* ap; // OK