Subject: [Boost-users] [thread] locking and time
From: Ernst Murnleitner (mur_at_[hidden])
Date: 2008-12-31 16:24:53
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