"Preston A. Elder" wrote:
On Wed, 14 Nov 2007 12:27:44 +0000, Preston A. Elder wrote:
This would be easily fixed by getting it to lock the internal lock on unlock (before the notify_all). Doing so would mean that the notify_all could not happen until B is in the wait.
And now I think about it, it should probably be a notify_one - there is no point waking up all threads when only one will be able to acquire the lock after an unlock.
You would then need to be a bit more careful in timed_lock(). if (!try_lock()) { mutex::scoped_lock sl(m_internal); while (!try_lock()) if (!m_cond.timed_wait(sl)) return try_lock(); } Alternatively, on timeout, you can return failure but only after resignaling condvar. (Timeout on condvar is allowed to "steal" concurrent signal.) unlock: m_mutex.unlock(); { mutex::scoped_lock sl(m_internal); } m_cond.notify_one(); Also note that such wrapping doesn't preserve destruction safety of Mutex ala POSIX pthread_mutex_t. To preserve it, m_mutex.unlock() must be done after signaling (or signaling must be done while holding m_internal lock which itself must be destruction safe as pthread_mutex_t). regards, alexander.