Re: [boost] Coding Guidelines for Integral Constant Expressions

From: John Maddock (john_at_[hidden])
Date: 2005-04-16 07:39:15

> 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.