From: "Rozental, Gennadiy" <gennadiy.rozental@thomson.com>
Trait - A class template parameterized on a single type that associates information with that type. A traits class, therefore, provides an external, named grouping of metainformation, behavior, or both for that type. A trait class is never passed as a template parameter; it's name is ubiquitous. A traits class never has state.
By state you mean non-static data members, yes?
Yes.
Policy - A class template passed to other templates for the purpose of providing a named grouping of metainformation, behavior, or both to those templates. Because it is a template parameter, different policy classes can be used as desired. In many cases, a policy class is used as a base class.
Well, apparently there is somebody who think the same as I do.
Thank you Rob, for your definitions. They seems sound and close to what I have in mind.
I'm hoping we can all come to agree on something that usefully distinguishes these terms. It is a hindrance to communication if everyone brings a different interpretation of the words to a conversation and if the two are thought to be completely interchangeable, then why use both? -- Rob Stewart stewart@sig.com Software Engineer http://www.sig.com Susquehanna International Group, LLP using std::disclaimer;