Hello This post may not be well suited to this mailing list. I have some questions about the lockable concept provided in boost. There are many "lock" types, and many "mutex" types. My main question is then : when should I chose a given lock type rather a given mutex type ? Given the fact that some of lock types are not thread-safe, if only one thread needs locks, why should I use one of these lock types and why shouldnt I use some mutex type ? Finally, what were the goals of providing so much different ways to lock/unlock resources ? (I may not be aware of all the concepts related to secure resource access) Since the "lock" et "mutex" types provide ways to lock/unlock access to resources, why are not these types defined under the same name ? Are the concepts they implements much more different than I think ? Thanks Axel