[boost] Threadsafe singleton - questions

I'm going through the documentation and now have some questions. I would hope that the documentation could be expanded to include answers to these questions. a) reference is made to a "lease" which sounds like a mutex to me. But its not obvious to me how this should be used. How does the compare with the pattern that I am more familiar with class s : singlton mutex m_mutex ... my_function(...){ scoped_lock(m_mutex); ... } OK - I've looked again and I think its clear to me how this is to be used. We need a tutorial here !!!! b) reference is made to boost::restricted which I couldn't find anywhere. Robert Ramey