[derivation] (original) (raw)

16 Library introduction [library]

16.5 Library-wide requirements [requirements]

16.5.5 Conforming implementations [conforming]

16.5.5.12 Derived classes [derivation]

An implementation may derive any class in the C++ standard library from a class with a name reserved to the implementation.

Certain classes defined in the C++ standard library are required to be derived from other classes in the C++ standard library.

An implementation may derive such a class directly from the required base or indirectly through a hierarchy of base classes with names reserved to the implementation.

In any case:

• Every base class described asvirtualshall be virtual;
• Every base class not specified asvirtual shall not be virtual;
• Unless explicitly stated otherwise, types with distinct names shall be distinct types.178

All types specified in the C++ standard library shall be non-final types unless otherwise specified.