InputStream.read doesn't block read while waiting for data

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Greg Taylor - 04 Feb 2005 01:59 GMT

Using J# 1.0 library, it appears that while read is waiting for data, some
kind of "message pump" in VS 2003 allows events to fire - ON THE SAME THREAD.
So the call stack looks like:
<callback fn registered with Visual Studio event>
[<Non-user code>]
<my fn at the line where m_inputStream.read is called>
...

The callback is actually the UIHierarchy.SaveItem method for my own
UIHierarchy in VS 2003. I expected .read to block the thread COMPLETELY,
until data was available. Any ideas why it isn't?

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jeff - 05 Feb 2005 00:26 GMT

I'm no expert in this area but if you're doing a blocking read on a UI
thread, then this wouldn't be at all surprising. Generally speaking,
in the Windows environment, blocking on the UI thread can cause
deadlock.

-- jeff

> Using J# 1.0 library, it appears that while read is waiting for data, some
> kind of "message pump" in VS 2003 allows events to fire - ON THE SAME THREAD.
[quoted text clipped - 7 lines]
> UIHierarchy in VS 2003. I expected .read to block the thread COMPLETELY,
> until data was available. Any ideas why it isn't?

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Lars-Inge T?nnessen [VJ# MVP] - 08 Feb 2005 20:38 GMT

In addition, if you block a UI thread the UI will not respond to paint
messages when you eg switch windows. The result is a window that does not
refresh (e.g. it will be white). You should never completely block a UI
thread.

Regards,
Lars-Inge T?nnessen

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InputStream.read doesn't block read while waiting for data

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