Static casting in C++

[laserlight]

Could you give an reference to the stadard? It would be great if you cite it here.

Sure.

An lvalue of type "cv1 B", where B is a class type, can be cast to type "reference to cv2 D", where D is a class derived (clause 10) from B, if a valid standard conversion from "pointer to D" to "pointer to B" exists (4.10), cv2 is the same cv-qualification as, or greater cv-qualification than, cv1, and B is not a virtual base class of D. The result is an lvalue of type "cv2 D." If the lvalue of type "cv1 B" is actually a sub-object of an object of type D, the lvalue refers to the enclosing object of type D. Otherwise, the result of the cast is undefined.