Subj : Re: Predicate for pthread_cond_timedwait() ??
To   : comp.programming.threads
From : recvfrom@gmail.com
Date : Thu Mar 17 2005 01:59 pm

David Schwartz wrote:
> <recvfrom@gmail.com> wrote in message
> news:1111022385.023902.120750@l41g2000cwc.googlegroups.com...
>
> > Rather than mess with timers and signals in a threaded app,
> > I tried using pthread_cond_timedwait() for a condvar that
> > will never be signaled.  Is this a good approach?  It seems
> > to work fine.
>
>     It's adequate, but usleep/nanosleep would be cleaner.
>
> > Also, I assume this call should be wrapped
> > in a loop, since there is no guarantee that the call could
> > return for some 'other' reason (whatever that might be, I'm
> > not sure).
>
>     Right.
>
> > What should be the predicate for this loop?  A
> > zero return value?  E.g.:
> >
> > r = 0;
> > while (r == 0)
> >  {
> >    r = pthread_cond_timedwait (&x->condvar, &x->mutex, &ts);
> >  }
>
> More like:
>
> int ret;
> pthread_mutex_lock(&x->mutex);
> do
>   ret=pthread_cond_timedwait(&x->condvar, &x->mutex, &ts);
>    while(ret!=ETIMEDOUT);
> pthread_mutex_unlock(&x->mutex);

Thanks so much for your response!!!  All good pointers.  I may
try nanosleep too -- a bit more code to cover the interrupt case,
but the intent is more obvious.  Thanks again!

-r

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