Neither gcc (3.3.3) nor Metrowerks (don't remember version) seems to think that "enumVal1 | enumVal2" is an integral constant expression. This seems obvious in the case of operator| being overloaded, although Comeau online 4.3.3 *does* seem to swallow that without complaint, which greatly diminishes my expectations of being right and greatly adds to my confusion. However, gcc and Metrowerks seem to ban this even if operator| is not overloaded. I haven't found the standardese to motivate that yet. Someone set me straight, please!
I couldn't find anything about this except 5.19 where certain specific operators are banned, by deduction everything else should be legal I guess (but not overloaded operators obviously). I guess casting the enum types to int should fix the compiler error (you can even cast back to enum type afterwards if that's what you want), but obviously that only works if you know how wide the enum's are. John.