Re: Threads: condition::timed_wait

From: williamkempf_at_[hidden]
Date: 2001-10-12 12:25:04

--- In boost_at_y..., "George A. Heintzelman" <georgeh_at_a...> wrote:
> > --- In boost_at_y..., "George A. Heintzelman" <georgeh_at_a...> wrote:
> > Looking at your code it appears that you've misused the condition 
> > type (though I may be wrong since I can't see all of your code).  
> > Taking your description the whole process should be something 
more 
> > like this (poor implementation, but written this way for clarity 
of 
> > the concept):
> > 
> > // in parent thread when it terminates...
> > {
> >     boost::mutex::scoped_lock lock(child->mutex);
> >     child->teminate = true;
> > }
> > 
> > // in child thread...
> > { 
> >     boost::mutex::scoped_lock lock
> >     boost::xtime xt;
> >     xtime_get(&xt, boost::TIME_UTC);
> >     xt.sec += transmission_delay;
> >     while (!terminate) {
> >         if (!cond.timed_wait(lock, xt))
> >            break;
> >     }
> >     if (terminate)
> >         // handle termination here
> > }
> > // other processing here
> > 
> 
> Well, this wouldn't quite be what I wanted to do, though I had 
missed 
> the point that timed_wait returns whether it timed out or not, 
which 
> does simplify things somewhat.
> 
> In any case, the code you wrote illustrates my question better. The 
> documentation of timed_wait says that the lock parameter must 
fulfill 
> the ScopedTimedLock model, which boost::mutex::scoped_lock doesn't 
(I 
> don't think). My question is, is this an error in the 
documentation, or 
> is it really needed for some reason I don't see? In other words, 
would 
> the code you wrote above work? If not, it might be worth adding a 
note 
> as to why boost::timed_mutex::scoped_timed_lock would be needed...

I'll have to look at this.  It would be an error in documentation if 
that is what it says, yes.  Any scoped_lock variant will work here.

Bill Kempf