[Ace-users] [ace-users] how to force svc() to wait for the std::queue to fill up?

[Douglas C. Schmidt]

Hi Bob,

To ensure that we have proper version/platform/compiler information,
please make sure you fill out the appropriate problem report form
(PRF), which is in

$ACE_ROOT/PROBLEM-REPORT-FORM
$TAO_ROOT/PROBLEM-REPORT-FORM

or in

$ACE_ROOT/BUG-REPORT-FORM
$TAO_ROOT/BUG-REPORT-FORM

in older versions of ACE+TAO.  Make sure to include this information
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"guess" what version/platform/compiler/options you've using, which is
very error-prone and slows down our responsiveness.  If you don't use
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Naturally, we encourage and appreciate other members of the ACE+TAO
user community who can respond to questions that they have the answers
to.

>I have a task class which inherits MyTask : public
>ACE_Task<ACE_MT_SYNCH>. In my svc() I have a loop
>like:
>
>int MyTask::svc()
>{
>	ACE_OS::sleep(1);
>	while( !myQueue.empty() )
>	{
>                    // do something
>                    if( myQueue.size() == 0 )
>	             break;
>	}
>	return 0;
>}
>
>I do a wait() in the destructor.
>
>Things work fine if I sleep(), however if I do not the queue is not
>filled up and svc exits.
>
>Unfortunately I cannot use ACE_Message_Block() - I cannot serlialize
>my object.
>
>Is there any other way to get arround this problem without sleep()?

I think the heart of the problem here is that std::queue() is
non-synchronized.  It's not really clear what you are trying to do,
but you should probably take a look at the discussion of
ACE_Condition_Thread_Mutex in Chapter 10 of C++NPv1
<www.cs.wustl.edu/~schmidt/ACE/book1/>.  Naturally, the easiest thing
to do would be to simply use the ACE_Message_Queue that's part of
ACE_Task, as per the discussion in Chapter 6 of C++NPv2
<www.cs.wustl.edu/~schmidt/ACE/book2/>.

Thanks,

Doug
-- 
Dr. Douglas C. Schmidt                       Professor and Associate Chair
Electrical Engineering and Computer Science  TEL: (615) 343-8197
Vanderbilt University                        WEB: www.dre.vanderbilt.edu/~schmidt
Nashville, TN 37203                          NET: d.schmidt at vanderbilt.edu