Re: Timer Priority

From:
"William DePalo [MVP VC++]" <willd.no.spam@mvps.org>
Newsgroups:
microsoft.public.vc.language
Date:
Fri, 29 Jun 2007 19:32:02 -0400
Message-ID:
<ObHtzWquHHA.1168@TK2MSFTNGP02.phx.gbl>
"JoDeGr8" <johnemmatty@gmail.com> wrote in message
news:1183141978.626957.271920@j4g2000prf.googlegroups.com...

What will be the priority of the timer thread created using the
function SetTimer? Does it have a high priority? How can i increase
the priority of the timer thread?


If you want a timer to fire in a background thread, check the docs for
timeSetEvent() and perhaps timeBeginPeriod() and timeEndPeriod(). The docs
are silent on much of the implementation detail - for example they don't say
if all the callbacks for a "periodic" timer fire in the same thread or not -
except to say that the timer always fires in a thread different from the
caller's.

In any case it's way to roll your own timer if you have strong feeling as to
priority and threading model. Just call _beginthreadex() or AfxBeginThread()
in an MFC application and then have a thread procedure something like this
which I have not compiled:

 #include <windows.h>
 #include <mmystem.h>

 unsigned __stdcall TimerThreadProc(void *pv)
 {
  SetThreadPriority( GetCurrenThread(), SomeGoodPriority);

  // timeBeginPeriod(1); // Uncomment for high resolution timer

  while ( YourTerminationCondition )
  {
   Sleep(YourTimerPeriodInMillis);

   TimerCallback(Yada, Yada, Yada);
  }

  // timeEndPeriod(1); // End period only if begun above

  return 0;
 }

Regards,
Will
www.ivrforbeginners.com

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