Compiler Error C2569

'EnumOrUnion' : enum/union cannot be used as a base class

If you must derive a type from the specified union or enumeration, change the union or enumeration to a class or structure.

The following sample generates C2569:

// C2569.cpp
// compile with: /c
union ubase {};
class cHasPubUBase : public ubase {};   // C2569
// OK
struct sbase {};
class cHasPubUBase : public sbase {};