From: William Kempf (sirwillard_at_[hidden])
Date: 2000-08-10 16:41:47
--- In boost_at_[hidden], jpanzer_at_n... wrote:
> jsiek_at_l... wrote:
>
> > William Kempf writes:
> > > I wouldn't attach it to the condition, however. I'd pass the
> > > predicate into the wait. Thus the condition can be used to
track
> > > different criteria.
> > >
> > > cond.wait((free1 > 10)(a));
> >
> > Why would you want to use the same condition variable with
different
> > criteria? (why not just use a different condition variable)
>
> Example: Bounded queue. Producer thread adds an item only if
> the queue size is less than 100, else it waits. Consumer removes
> an item only if the queue size is greater than 0, else it waits.
Two
> different conditions, both of them dependent on the same
> variable.
>
> (Of course the producer also needs to be able to specify a timeout.)
This can be implemented with either one condition using multiple
criteria or two conditions. There isn't really an example (at least
that I can think of) where one or the other is the only solution.
The question is, which is the better solution for the specific
problem.
William Kempf