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    <p>The page on <a href="http://msdn.microsoft.com/en-us/library/fs2xkftw.aspx#Y754" rel="nofollow">MSDN here</a> never actually explictly states that Dispose methods are not threadsafe, but to my reading, their code implies that no, they are not threadsafe and you need to account for that if needed.</p> <p>Specifically the comments in the example code:</p> <pre><code>// This class shows how to use a disposable resource. // The resource is first initialized and passed to // the constructor, but it could also be // initialized in the constructor. // The lifetime of the resource does not // exceed the lifetime of this instance. // This type does not need a finalizer because it does not // directly create a native resource like a file handle // or memory in the unmanaged heap. public class DisposableResource : IDisposable { private Stream _resource; private bool _disposed; // The stream passed to the constructor // must be readable and not null. public DisposableResource(Stream stream) { if (stream == null) throw new ArgumentNullException("Stream in null."); if (!stream.CanRead) throw new ArgumentException("Stream must be readable."); _resource = stream; _disposed = false; } // Demonstrates using the resource. // It must not be already disposed. public void DoSomethingWithResource() { if (_disposed) throw new ObjectDisposedException("Resource was disposed."); // Show the number of bytes. int numBytes = (int) _resource.Length; Console.WriteLine("Number of bytes: {0}", numBytes.ToString()); } public void Dispose() { Dispose(true); // Use SupressFinalize in case a subclass // of this type implements a finalizer. GC.SuppressFinalize(this); } protected virtual void Dispose(bool disposing) { // If you need thread safety, use a lock around these // operations, as well as in your methods that use the resource. if (!_disposed) { if (disposing) { if (_resource != null) _resource.Dispose(); Console.WriteLine("Object disposed."); } // Indicate that the instance has been disposed. _resource = null; _disposed = true; } } } </code></pre>
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    1. POThread-Safety of Dispose methods?
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    1. USDavid Hall
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    1. COYeah, I noticed this; it's an interesting example. Unfortunately the documentation writers aren't always on par with the BCL programmers, and it's not explicit about the case of BCL types anyway. I suspect you're right about the general lack of the guarantee though.
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      1. USNoldorin
    2. COOn a related note, if the Dispose method is thread-safe, shouldn't all methods that use disposable resources (i.e. do a `if (_disposed)` check) also be thread-safe with respect to disposing (i.e. use a lock)?
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      1. USNoldorin
    3. CO@Noldorin: That logic is why I'm 99.999...% sure that 'instance members' includes `Dispose()` when the docs are discussing thread safety. `Dispose()` *is an instance member*, so it should have the same thread-safety properties as the rest.
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      1. USAndrew Barber
 

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