Hello, I have some questions about threads. It would be very nice if somebody could clarify. 1) recursive_timed_mutex: It is possible to use a time period for locking of a recursive_timed_mutex by using the approprioate timed_lock(). But there is not lock class with such a constructor? 2) (recursive timed) shared mutex: Is it not possible to lock with a period of time instead of ptime? 3) change of system time: What happens in a timed_lock if the system time is advanced by e.g. one hour? Is there a difference of using ptime or time_period? 4) read/writer mutex: if there are some recursive locks by one thread and this thread should become the writer, do I run in a deadlock? 5) What is the meaning of the various ..._lock_t (e.g. )? Is there a documentation? ad 1) There seems only to be a constructor with ABSOLUTE time: unique_lock(Lockable & m,boost::system_time const& abs_time) ad 2) There seems no possibility to use boost::posix_time::time_period for locking. ad 3) If the clock is set to one hour in the future. I think a timed_lock could take one hour at this moment? If yes, does it happen also if I give a time period? ad 4) if it is possible to recusively lock in one thread, it should be possible to make the thread a writtrer thread (exclusive owner) independently on how often it was locked before. Is this possible? ad 5) Only internal usage?: unique_lock(Lockable& m_,adopt_lock_t); unique_lock(Lockable& m_,defer_lock_t); unique_lock(Lockable& m_,try_to_lock_t) Thank you in advance, Greetings, Ernst