Re: [boost] Re: Threads: condition::timed_wait

From: George A. Heintzelman (georgeh_at_[hidden])
Date: 2001-10-11 17:07:10

> --- 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...

George Heintzelman
georgeh_at_[hidden]