[boost] Re: [Boost.Thread] mutex Win32 implementation changes

From: Alexander Terekhov (terekhov_at_[hidden])
Date: 2004-07-20 14:32:02

Alexander Terekhov wrote:
> 
> Peter Dimov wrote:
> [...]
> > > I have PS/2 Model 80 (with 64 Megs) "tank" at home (in addition to
> > > A31p ThinkPad ;-) ).
> >
> > He he. OK, if you had CAS (PS/2 Model 70 486) how would you do it?
> 
> Ok, you owe me a "Blue Lightening" processor upgrade. ;-) How about
> 
>   void lock() throw() {
>     while (int lock_status = m_lock_status.cas(0, 1, msync::ddacq))
>       if (lock_status < 0 || m_lock_status.cas(1,-1, msync::ddacq))
>         m_retry_event.wait();

Err.      m_retry_event.wait(), m_retry_event.set();

>   }
> 
>   bool trylock() throw() {
>     return !m_lock_status.cas(0, 1, msync::acq);
>   }
> 
>   bool timedlock(absolute_timeout const & timeout) throw() {
>     while (int lock_status = m_lock_status.cas(0, 1, msync::ddacq))
>       if (lock_status < 0 || m_lock_status.cas(1,-1, msync::ddacq))
>         if (!m_retry_event.timedwait(timeout)) m_retry_event.set(),
>           return !m_lock_status.swap(1, msync::acq);
>     return true;
>   }

Forget it. timedlock() would make it "posix unsafe". lock_queue is
the way to go.

regards,
alexander.