QuoteOriginally posted by: outrunI like the formal classification, the "contract", and having a design principle. I have not enough knowledge yet to suggest a pick.Related to this, I read a debate om boost dev about predictable and unpredictable errors. Calling sqrt(-1) is an predictable error, programming errors will be in that class. Getting a file from a remote host can give unpredictable errors, eg when there is a hardware failure. Don't know what the point is I'm trying to make We should handle the 2nd, but not necessarily the first (when we optimize for speed) ?I think #1 is an exception (logic error) while #2 is a fault/failure in BM's classification. The STL has categories for a number of these. And Math Toolkit also has some classes, which might be useful as well.Some possible issues down the line:1. Exceptions and threads2. Is Boost Exception used?3. (Crazy) use signals to 'emulate' exception handling?? in the 'throw' class we have a signals that emits to composite slots (can be connected/disconnected on the fly).