David Abrahams writes:
I think your definitions are mostly on target, but I think where you go wrong is that traits/policies has less to do with how a template is defined than how it's used.
To me a traits class provides information to a template class that gives (possibly platform or type dependant) information. For example, the decimal point character (100.00 or 100,00?) would be in a traits class (I know this is in a locale, but this is an example). Another example would be a format string to use as a separator between items in a list, depending on whether a character, string, wide character, wide string, etc are used. A policy class provides functional, i.e. behavioural, information. Examples include string comparison, pointer validation (for smart pointers) and error handling (e.g. smart pointers and how to handle InvalidPointer - nothing, throw std::exception, assert failure, etc.). Regards, Reece _________________________________________________________________ Express yourself with cool new emoticons http://www.msn.co.uk/specials/myemo