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copied!<p>You're correct that you do not need a special instruction to atomically read a 32bit integer, however, what that means is you will get the "whole" value (i.e. you won't get <em>part of one write and part of another</em>). You have no guarantees that the value won't have changed once you have read it.</p> <p>It is at this point where you need to decide if you need to use some other synchronization method to control access, say if you're using this value to read a member from an array, etc.</p> <hr> <p>In a nutshell, <strong>atomicity</strong> ensures an operation happens completely and indivisibly. Given some operation <code>A</code> that contained <code>N</code> steps, if you made it to the operation right after <code>A</code> you can be assured that all <code>N</code> steps happened in isolation from concurrent operations.</p> <p>If you had two threads which executed the atomic operation <code>A</code> you are guaranteed you will see only the <strong>complete</strong> result of <em>one of the two</em> threads. If you want to coordinate the threads, atomic operations could be used to create the required synchronization. But atomic operations in and of themselves do not provide higher level synchronization. The <code>Interlocked</code> family of methods are made available to provide some fundamental atomic operations.</p> <p><strong>Synchronization</strong> is a broader kind of concurrency control, often built around <em>atomic</em> operations. Most processors include memory barriers which allow you to ensure all cache lines are flushed and you have a <strong>consistent</strong> view of memory. Volatile reads are a way to ensure consistent access to a given memory location.</p> <p>While not immediately applicable to your problem, reading up on ACID (atomicity, consistency, isolation, and durability) with respect to databases may help you with the terminology.</p>

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