RE: [Quickfix-developers] Incorrect threading function.

[Daniel M. <Dan...@ma...>]

Tim,
Have you checked these changes into CVS ?

Daniel May
da...@ma...

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Message: 2
From: Timothy Yates <ty...@pa...>
To: "'qui...@li...'"
	 <qui...@li...>
Date: Thu, 20 Nov 2003 16:06:58 -0000
Subject: [Quickfix-developers] Incorrect threading function.

I am using the Java quickfix API and running on a fast (3GHz) processor
on Windows XP.

I have encountered a number of threading problems.

1. It is quite common for QuickFIX to lock up in Acceptor.stop().  The
lock-up occurs due to incorrect implementation of
thread_spawn/thread_join.
These should use _beginthreadex, not _beginthread.  In the current
implementation (using _beginthread), the call too WaitForSingleObject()
generally fails because the handle it is waiting for has already been
closed automatically by _beginthread.  Sometimes, WaitForSingleObject()
blocks indefinitely even though the acceptor thread has exited.  This
may be because it is waiting on an incorrect handle for which no event
is likely to be signalled.  In any case, the Windows documentation
advises against using _beginthread and WaitForSingleObject together.

2. When stopping a SocketAcceptor there is a race condition between
completion of the acceptor thread function and destruction of the
SocketServer object.  Since the thread function uses the SocketServer
object,  it should not be destroyed until the thread function has
completed.
I'm not sure that this is causing problems, but it looks dangerous.

3. The stack trace facility (QF_STACK_PUSH/QF_STACK_POP) does not work
on Windows.  This is due to incorrect implementation of thread_self().
GetCurrentThread() returns a pseudo handle, which seems to be the same
irrespective of thread.  I replaced this with a call to
GetCurrentThreadId().

Tim Yates
Lead Developer
Patsystems (US) LLC
141 West Jackson Boulevard
Chicago 60604, USA
Tel +1 (312) 542-1336
www.patsystems.com=20


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