Messages in this thread | | | Date | Tue, 27 Oct 2009 03:23:12 -0700 | Subject | Re: Difference between atomic operations and memory barriers | From | "Leonidas ." <> |
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On Tue, Oct 27, 2009 at 3:21 AM, Michael Schnell <mschnell@lumino.de> wrote: > Leonidas . wrote: >> >> any_t *ptr = something; >> >> is always atomic even on SMPs without using locks, barriers then my >> doubt is cleared. Thanks. > > I assume that this only holds if the pointer (not the thing it points > to) is denoted as volatile. > > -Michael >
I dont think so, volatile would only ensure no caching, so some cpus might see the cached pointer (this is where you would want to use barriers), but pointer assignment would still be atomic.
-Leo.
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