c++ - Making a template based on an internal class -

i trying make class templated on 1 of internally defined classes.

i thought forward declaring relevant classes, i'd okay.
keep getting compile-time errors like:

use of undefined type querygetcustomer reply uses undefined class querygetcustomer 

is there way can template querygetcustomer on class reply, when class reply internal querycustomer, shown in code?

class querygetcustomer; class querygetcustomer::reply; // error: use of undefined type querygetcustomer                                // error: reply uses undefined class querygetcustomer  class querygetcustomer :    public basequery<querygetcustomer::reply> { public:     class reply { [....] }; }; 

p.s. have templating structure working when class reply external (global) querygetcustomer class.

however, reply makes sense within query, i'd have internal class.

whole thing fails on trying forward declare inner class.

you cannot forward declare inner type of class. that's it.