Re: Problem with PulseEvent

From:

"William DePalo [MVP VC++]" <willd.no.spam@mvps.org>

Newsgroups:

microsoft.public.vc.language

Date:

Thu, 28 Sep 2006 11:54:18 -0400

Message-ID:

<urqVcZx4GHA.1012@TK2MSFTNGP05.phx.gbl>

"Gerd" <kehrer@de.ibm.com> wrote in message
news:uNg9uSx4GHA.900@TK2MSFTNGP04.phx.gbl...

we discovered multiple hang situations of our C++ application.
Investigation turned out, that a thread waiting for an event doesn't wake
up while the code which triggers the event (using the function
'PulseEvent') was executed multiple times.
...
Note This function is unreliable and should not be used. It exists mainly
for backward compatibility. For more information, see Remarks.

The 'remark' section describes exactly the behaviour we see and does NOT
mention the debigging environment.

What we would like to know is:

1. Can the behaviour described in the online documentation of 'PulseEvent'
occour outside the debugging environment?

2. If the answer to question 1 is yes: What alternatives exist as
replacement for 'PulseEvent'?

You quoted the section of the documentation in which the function is
described to be unreliable. It's widely known. Raymond Chen agrees and says
so in his blog.

http://blogs.msdn.com/oldnewthing/archive/2005/01/05/346888.aspx

IMO, it would be wise to heed the documentation and forego the use of the
function. If you describe what you need to do and not how you need to do it,
someone may suggest an alternative.

Without knowing the specifics of your task, I'd suggest looking into
semaphores. If you were using PulseEvent() to unblock only one of several
waiting threads, you may be able to use a semaphore with a "count" of 1.

Regards,
Will