Question

C++11 adds enum classes, which are stronger-typed enums – values of enum classes will not be implicitly converted to values of other enum classes or integers, and forward-declarations are permitted by virtue of an explicit size specifier.

Is it possible to pass values of such enumerations to varargs functions and remain within standards-defined behavior? Within implementation-defined behavior?

Answer 1

Yes, you can. 5.2.2/7 explicitly allows arguments of any enumeration type. Unscoped enum values are integer promoted, but scoped enums (the enum class ones) are not.

Of course you still have to be careful in the implementation of the function.