[Qt-interest] Is there a way to process all queued eventsbefore continuing?

[Scott Aron Bloom]

One thing you might try... 

 

If you are trying to tell a worker thread "process everything", you cant
call the qapp->processEvents since that only works on the calling
thread..

 

Create a slot on the worker thread, then connect to it in Blocking
manner, and send a "process all" type of signal

 

Scott

 

 

 

From: qt-interest-bounces at trolltech.com
[mailto:qt-interest-bounces at trolltech.com] On Behalf Of Preet
Sent: Wednesday, December 16, 2009 8:50 AM
To: qt-interest at trolltech.com
Subject: Re: [Qt-interest] Is there a way to process all queued
eventsbefore continuing?

 

One thing that is briefly mentioned in the docs is to call
QTimer::singleShot with a timeout of zero. This is supposed to 'timeout'
after all pending events are processed. I'd appreciate if someone could
expand on this... what happens exactly -- is the QTimer event simply
posted to the end of the current event queue?

 

I have a QThread servicing a device which constantly tacks on events to
its event queue. To 'block' the thread, I block the device, but during
the interim between the call to block the device, and it actually being
executed, more events may be placed on the queue. I need to process
these additional events before I can continue. I'll update this if
QTimer works as expected.

 

edit:

I just got your reply Bradley, I'll give it a shot.

 

Thanks all!

 

On Wed, Dec 16, 2009 at 11:46 AM, Bradley T. Hughes
<bradley.hughes at nokia.com> wrote:

Andre Somers wrote:
> Preet wrote:
>> Hi,
>>
>> Thanks for the reply. I'm trying to clear all pending events in my
>> secondary thread's event queue. Doesn't processEvents do this for my
>> main Gui thread? (not what I want to do). There's no
>> QThread::ProcessEvents() function... I'm looking for such an analog.
>>
>> -Preet
> Interesting question. QEventLoop has a processEvents, but I don't see
a
> method in QThread to access the thread's event loop... Perhaps the
> source could give you a pointer if there is an (undocumented) loophope
> to get it anyway?

I'll do you one better, here's how do to it (and it's documented):

http://qt.nokia.com/doc/4.6/qcoreapplication.html#processEvents

"void QCoreApplication::processEvents ( QEventLoop::ProcessEventsFlags
flags
= QEventLoop::AllEvents )   [static]

Processes all pending events for the calling thread according to the
specified flags until there are no more events to process."

--
Bradley T. Hughes (Nokia-D-Qt/Oslo), bradley.hughes at nokia.com
Sandakervn. 116, P.O. Box 4332 Nydalen, 0402 Oslo, Norway

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