Is there any notion of recursive locking for the read-write mutex? Specifically, if a thread has a write-lock on a mutex, is there any way to have recursive read- or write-locks on that mutex pass immediately? Notionally, it seems that permission to write to something presumes permission to read it. However, when I try to read-lock a mutex which is already write-locked (in the same thread), I get deadlock. I would be happy to use the promote-demote functionality of the read_write_lock, but the following excerpt from the documentation scares me: "[The promote() function] throws boost::lock_error if . . . the lock cannot be promoted because another lock on the same mutex is already waiting to be promoted." This makes it sound like there is no way to guarantee that you can promote a lock, even with unbounded blocking. Is this the case? Thanks for any help on this. -- Austin Bingham "If I were creating the world I wouldn't mess about with butterflies and daffodils. I would have started with lasers, eight o'clock, Day One!" Evil