Re: Thread Deadlock Problem.

From:
"Alexander Grigoriev" <alegr@earthlink.net>
Newsgroups:
microsoft.public.vc.mfc
Date:
Fri, 12 Feb 2010 19:45:42 -0800
Message-ID:
<ugWbF8FrKHA.4220@TK2MSFTNGP05.phx.gbl>
Do you create the threads with m_bAutoDelete=FALSE?

"Keaven Pineau" <keavenpineau-no-more-spam@videotron.ca-no-more-spam> wrote
in message news:e2v2KMCrKHA.4492@TK2MSFTNGP05.phx.gbl...

Hello all,
I did a dialog application with an utility class with 2 working threads in
it that are calling callback functions of the xxxdlg class.

Thead A is my main working thread. This thread his waiting on 2 events :
1- Quit Event
2- Optional callback call Event

This thread is calling a callback function on every
WaitForMultipleObjects() timeout, here 5000 ms.

Thread B is an optional thread that can be enable/disable at anytime.
This thread his waiting only a quit Event and when WaitForSingleObject()
timeout it is setting the Optional Event of Thread A via SetEvent().
Timeout here is 15 000 ms.

Each Thread are calling AfxEndThread(0,FALSE); at the end and the control
function is waiting on A->m_hThread and/or B->m_hThread before deleting
their respective object.

Now, if I am not enabling thread B. I can start and end Thread A without
any issue. If I start both thread A and B and I can also quit them
without problem if they were both running. Now , If I start both thread A
and B and stopping thread B and waiting a 10 seconds when I will try to
stop thread A the WaitForSingleObject() on his handle will deadlock.

I have found out that it is related with the event I am using for telling
thread A to execute the optional callback. If I simply put the SetEvent()
in comment, the problem never occurs.

Any idea, why this is happening?

Thank you

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