Subj : Re: really simple portable eventcount...
To   : comp.programming.threads
From : Joe Seigh
Date : Sun Mar 06 2005 09:19 am

On Sat, 5 Mar 2005 22:54:59 -0800, SenderX <xxx@xxx.com> wrote:

Plus, I don't think you need to optimize wait in any case.  It's already
going to be slow.  So the compare of the eventcount outside of the locked
region can be removed.  It's a pretty small window between the test of
the condition and the test of the eventcout.  The eventcount is unlikely
to have been set in that amount of time so that test doesn't buy you
that much.  The later test is necessary since you need to test it before
potentially blocking.

>
>
>   int wait( int cmp )
>   {
>     int local = m_ec & 0x7FFFFFFF;
>
>     if ( local == cmp )
>     {
>       pthread_mutex_lock( &m_mutex );
>
>       local = m_ec & 0x7FFFFFFF;
>
>       if ( local == cmp )
>       {
>         ++m_waiters;
>
>         pthread_cond_wait( &m_cond, &m_mutex );
>       }
>
>       pthread_mutex_unlock( &m_mutex );
>     }
>   }
>
> };
>




-- 
Joe Seigh

.