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POIs C#'s using statement abort-safe?
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copied!<p>I've just finished reading "C# 4.0 in a Nutshell" (O'Reilly) and I think it's a great book for a programmer willing to switch to C#, but it left me wondering. My problem is the definition of <code>using</code> statement. According to the book (p. 138),</p> <pre><code>using (StreamReader reader = File.OpenText("file.txt")) { ... } </code></pre> <p>is precisely equivalent to:</p> <pre><code>StreamReader reader = File.OpenText("file.txt"); try { ... } finally { if (reader != null) ((IDisposable)reader).Dispose(); } </code></pre> <p>Suppose, however, that this is true and that this code is executed in a separate thread. This thread is now aborted with <code>thread.Abort()</code>, so a <code>ThreadAbortException</code> is thrown and suppose the thread is exactly after initializing the reader and before entering the <code>try..finally</code> clause. This would mean that the reader is not disposed!</p> <p>A possible solution would be to code this way:</p> <pre><code>StreamReader reader = null; try { reader = File.OpenText("file.txt"); ... } finally { if (reader != null) ((IDisposable)reader).Dispose(); } </code></pre> <p>This would be abort-safe.</p> <p>Now for my questions:</p> <ol> <li>Are authors of the book right and the <code>using</code> statement is not abort-safe or are they wrong and it behaves like in my second solution?</li> <li>If <code>using</code> is equivalent to the first variant (not abort-safe), why does it check for <code>null</code> in <code>finally</code>?</li> <li>According to the book (p. 856), <code>ThreadAbortException</code> can be thrown anywhere in managed code. But maybe there are exceptions and the first variant is abort-safe after all?</li> </ol> <p><strong>EDIT:</strong> I know that using <code>thread.Abort()</code> is not considered good practice. My interest is purely theoretical: how does the <code>using</code> statement behave <strong>exactly</strong>?</p>

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