[boost] "joinable"

Seems to me that if we have "detach()," it we should be asking whether a thread is "attached()," rather than "joinable()." Our documentation says "if *this refers to a thread of execution..." all over it, which would seem to indicate that joinable() is an important question even when you're not about to join(). Thoughts? -- Dave Abrahams BoostPro Computing http://www.boostpro.com