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PODeadlock clarification?
 

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    <p><em>Maybe there is other interpretation of "Dead Lock" but AFAIK :</em> </p> <p><a href="http://books.google.co.il/books?id=t1de8nSVYnkC&amp;pg=PA882&amp;lpg=PA882&amp;dq=%22A%20deadlock%20happens%20when%20two%20threads%20each%20wait%20for%20a%20resource%20held%20by%20the%20other,%20so%20neither%20can%20proceed.%22&amp;source=bl&amp;ots=24seVuLjaz&amp;sig=ApUJDxRvzk0WEMoq67JVJBeeE8s&amp;hl=en&amp;sa=X&amp;ei=z9YnUZ_zIorLswb1wIHYBA&amp;redir_esc=y#v=onepage&amp;q=%22A%20deadlock%20happens%20when%20two%20threads%20each%20wait%20for%20a%20resource%20held%20by%20the%20other,%20so%20neither%20can%20proceed.%22&amp;f=false" rel="nofollow noreferrer">reference</a></p> <blockquote> <p>A deadlock happens when <strong>two threads each wait for a resource held by the other</strong>, so neither can proceed.</p> </blockquote> <p>But I've seen couple of answers here on SO which claims that a long wait ( without waiting for each other) is also a deadlock : </p> <p><strong><a href="https://stackoverflow.com/a/894071/859154">Example #1</a></strong></p> <pre><code>namespace ConsoleApplication7 { public class Program { public static void Main(string[] args) { LockableClass lockable = new LockableClass(); new Thread(new ParameterizedThreadStart(BackgroundMethod)).Start(lockable); Thread.Sleep(500); Console.Out.WriteLine("calling Reset"); lockable.Reset(); } private static void BackgroundMethod(Object lockable) { lock (lockable) { Console.Out.WriteLine("background thread got lock now"); Thread.Sleep(Timeout.Infinite); } } } public class LockableClass { public Int32 Value1 { get; set; } public Int32 Value2 { get; set; } public void Reset() { Console.Out.WriteLine("attempting to lock on object"); lock (this) { Console.Out.WriteLine("main thread got lock now"); Value1 = 0; Value2 = 0; } } } } </code></pre> <blockquote> <p>Pardon me but all I see here is a pure lock that hasn't been released. it is not a situation both threads waiting for another. The Thread here <strong>does NOT</strong> wait for the main thread to finish.</p> </blockquote> <hr> <p><strong><a href="https://stackoverflow.com/a/728920/859154">Another example #2</a></strong></p> <pre><code>class ILockMySelf { void doThat() { lock(this){ ... } } } class WeveGotAProblem { ILockMySelf anObjectIShouldntUseToLock; void doThis() { lock(anObjectIShouldntUseToLock) { // Following line should run in a separate thread // for the deadlock to happen anObjectIShouldntUseToLock.doThat(); } } } </code></pre> <p>Same here. the thread which runs <code>doThis</code> is NOT waiting for the "separate thread" which will run <code>doThat</code></p> <p><strong>Question :</strong> </p> <ul> <li>Are Deadlocks involved here? </li> </ul>
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    1. COThe second example is not a deadlock.
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    2. COThere is no deadlock in example 2. Assume two threads each run the doXXX methods and ILockMyself is the same reference. If T1.ILockMyself.doThat takes the lock first, nothing happens because doThat has no mutual ressource which T2.WeveGotAProblem has locked so it runs to completion and releases the lock. If T2.WeveGotAProblem.doThis takes the lock first, there will be a nested lock on the same reference which is released in order,no issue there.
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    3. CO@Alex Thank you for the **detailed** reply .this should be posted to David's answer ( or better - as an answer) . cause he claims the opposite.....
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