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From: markspace <-@.>
Newsgroups: comp.lang.java.programmer
Subject: Re: Volatile happens before question
Date: Tue, 17 Jan 2012 12:09:24 -0800
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On 1/17/2012 11:06 AM, Daniel Pitts wrote:

> On 1/17/12 10:41 AM, markspace wrote:
>> He's reading "b" first. He stores b in bStore, and then checks "a".

> He is reading b first.


Right.  "b" is not volatile.  So we can't say anything at all about the 
value of "b".  Full stop.


> If b=1, that means a MUST be true.

No, if b = 1, it could just be a random value made up by the CPU.


Check Java Concurrency in Practice.  "Programs with data races have no 
useful defined semantics."  That's exactly what Brian Goetz says, and 
this is what he's talking about.  Reads and writes no longer work if you 
obviate synchronization.