------- Additional Comments From timb at bluearc dot com 2005-01-27 17:50 ------- There's certainly a good case for warning about packing that's likely not to have the desired results - we've been bitten by that before. But that doesn't really apply to all non-POD; you can define a subset safe-non-POD (broadly speaking, no virtual functions/bases and (recursively) no unsafe non-static data members) where everything still has reasonably predictable representations and you don't need extra space for polymorphism magic.
So if you do go in that direction, please consider separate warnings for those non-POD types that can nevertheless safely be packed and those that can't. Classes made non-POD through fairly innoccuous constructions - e.g. constructors, simple inheritance - are often useful in abstracting hardware registers, data formats, etc. We'd be swamped in warnings if we got one for every packed non-POD, but we definitely do want to know if there's something that's actually going to mess things up. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17519
