Reusing enum values in separate enum types

For those using C++11, you may prefer to use:

enum class Foo

instead of just:

enum Foo

This provides similar syntax and benefits from as namespaces. In your case, the syntax would be:

enum class DeviceState { UNKNOWN, ACTIVE, DISABLED, NOTPRESENT, UNPLUGGED };
DeviceState deviceState = DeviceState::UNKNOWN;

Note that this is strongly typed so you will need to manually cast them to ints (or anything else).

You can, and should, include your enums in a namespace:

namespace DeviceState
{
    enum DeviceState{ UNKNOWN, ACTIVE, DISABLED, NOTPRESENT, UNPLUGGED };
}
namespace DeviceType
{
    enum DeviceType{ UNKNOWN, PLAYBACK, RECORDING };
}

//...

DeviceType::DeviceType x = DeviceType::UNKNOWN;