Question

Basically I need to expose several constants from unmanaged C++ to my C# library. The following approach works, but I think it smells:

In my unmanaged C++ code:

class Mappings
{
public:
    static const int North = 0 ;
    static const int West = 1 ;
    static const int East = 2 ;
    static const int South = 3 ;

In my managed C++ layer:

public:
    static const int North = Mappings::North ;
    static const int West = Mappings::West ;
    static const int East = Mappings::East ;
    static const int South = Mappings::South ;

Is there a cleaner/shorter way, so that I do not have to duplicate my code twice?

Answer 1

Use the public enum class keywords to declare a managed enumeration type. And yes, this is ugly since you cannot export the native C++ enumeration. Repeating yourself is unfortunately required.

C++11 adopted the enum class keyword as well but it is still distinct from the managed version. This caused a syntax ambiguity in C++/CLI since both language flavors now use the same keywords. The compiler can see the distinction from the accessibility keyword (use public or private), it is not valid for native C++.