RE: [Quickfix-users] why threads

[Bud G. <bud...@ya...>]

Hey,

It's kind of a hard time to try and answer the question because there
are major differences between QuickFix 1.4.x or earlier and 1.5.0 when
it comes to threads and the onRun method, you didn't state which version
of QuickFix you were using.  But if you use the code for backwards
compatibility that Oren describes in the 1.5.0 Release Announcement or
you're using 1.4.x then you can really ignore the onRun method and just
put a while (true) sleep(1000000); statement as the body of the onRun
method or something similar. It may take up an additional thread that
sleeps a lot; but not a big deal, IMHO.  Now, when you write your
callbacks for toApp/fromApp (or toAdmin/fromAdmin) they will be executed
within a single thread and any concerns you have for making the
application thread safe aren't necessary.  You code the callbacks just
like the app is a single threaded, event driven application w/o having
to worry about contention between global variables, containers or
whatever.

If you want to use 1.5.0 as it was intended, it's really easier and
reduces the thread count.  But there are not a lot of examples (at this
point).  First move the while (true) sleep (1000000); to your main()
routine (or do something more useful) just after your call to the
initiator.start() method and don't bother overriding the onRun method.
This make the main thread wait forever.  Once again all of the callbacks
you overrode from the Application class will be within the same thread
and you don't have to worry, plus there's 1 less thread.

If you're really concerned, QuickFix has a SynchronizedApplication class
to use instead of the Application class that uses a set/clear a mutex
around all of the FIX protocol callbacks.

I do disagree with your concern over multiple threads being used by
QuickFix, the fact that I don't have to worry about QuickFix taking care
of its own threads under Unix or Windows has made my life much easier.
In the FIX apps I've written there always seems to be something else I
have to deal with; another socket connection for non-FIX protocols or a
market data feed vendor's API, etc. These situations seem to be more
easily handled by another thread; even though I have to deal with the
synchronization issues between the data classes/containers I've created
to share the info.

Take care,
Bud

-----Original Message-----
From: qui...@li...
[mailto:qui...@li...] On Behalf Of
ma...@Ge...
Sent: Friday, May 30, 2003 2:55 PM
To: QuickFix
Subject: [Quickfix-users] why threads


Hi,

I am using SocketInitiator expecting to have a non-threaded application.
However, when my application starts in my debugger (gdb) it reports
three
threads running.  Why?  What do I have to do to make my application
thread
safe?

  (gdb) run
  Starting program: /home/marc/src/quickfix/atoms/atoms=20
  [New Thread 1024 (LWP 21677)]
  [New Thread 2049 (LWP 21678)]
  [New Thread 1026 (LWP 21679)]
  [Switching to Thread 1026 (LWP 21679)]

  Breakpoint 1, Application::onRun (this=3D0xbffffbf0) at
Application.C:188
  (gdb)=20

Thank you,
Marc


PS. Hi Aaron!!!!
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Marc Schwarzschild                                     1-646-825-2163
Gerber Capital Management Inc.                      120 Broadway, NYC

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