Compiler Error C2254

'function' : pure specifier not allowed on friend functions

The specified friend function was specified as pure virtual.

The following is an example of this error:

class A
{
public:
   friend void func1() = 0;   // error, func1 is friend
   void virtual func2() = 0;  // OK, pure virtual
   friend void func3();       // OK, friend not virtual nor
};                            //     pure
void func1() {};
void func3() {};