Subj : Re: [.NET] Volatile Fields
To   : comp.programming.threads
From : David Schwartz
Date : Sun Sep 18 2005 12:28 am


"Cool Guy" <coolguy@abc.xyz> wrote in message 
news:9bux5adfnj7d$.dlg@cool.guy.abc.xyz...
> Joe Seigh <jseigh_01@xemaps.com> wrote:
>
>> Cache has no effect on read/write ordering.  It's the memory model that 
>> does.
>> You could have a system without cache and it would still have the same 
>> issues
>> with read/write ordering.  So trying to imagine what is happening with a
>> hardware entity, which by definition you can't see, only serves to 
>> confuse
>> yourself.
>
> My confusion arises from the fact that only *one* of those fields is
> volatile in the example linked from the OP, and not *both* of them, which
> leads me to believe that the one field that isn't volatile could be
> read/written from/to the cache instead of from/to main memory and thus the
> code isn't thread-safe.

    What do caches have to do with thread-safety? It's read/write *ordering* 
that creates thread safety problems, not caches.

    DS

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