Subj : Re: [.NET] Volatile Fields [correction]
To   : comp.programming.threads
From : Alexander Terekhov
Date : Mon Sep 19 2005 09:48 pm


David Schwartz wrote:
> 
> "Cool Guy" <coolguy@abc.xyz> wrote in message
> news:1cgq3c5ccqz6r.dlg@cool.guy.abc.xyz...
> 
> > David Hopwood <david.nospam.hopwood@blueyonder.co.uk> wrote:
> 
> >> The write to Y is not performed as a single atomic event; it has to be
> >> modelled
> >> as two events: "Y = 1 is performed with respect to processor 2" and "Y =
> >> 1 is
> >> performed with respect to processor 3". So it can happen that processor 2
> >> sees
> >> Y == 1 before writing Z = 1, but processor 3 does not see Y == 1 until
> >> after
> >> it sees Z == 1.
> >
> > <snip>
> >
> > So it's impossible to make such code thread-safe, then?
> 
>     With memory barriers, yeah. Just use mutexes or other *appropriate*
> synchronization mechanisms. ;)

http://www.opengroup.org/austin/mailarchives/ag/msg08586.html

regards,
alexander.

.