[Qt-interest] question about threads in console application

[franki]

Tuesday 22 of March 2011 13:41:11 Anton Chernov napisał(a):
> A clean main function sounds great! And if all other functions are
> clean too you are programming with qt!
>
> The thing is that you get a reaction on a event from the other thread
> only in the qApp->processEvents(); If you do some heavy stuff you can
> call that method to see if there is some processing to do.

So in my case if i have handler for qDebug function defined and installed 
inside main(), then every thread that tries to use qDebug must wait until 
function from main have finished, because qDebug call is processed as an 
event inside main qApp right?

Marek

>
> To make it clean take a look at QtConcurrent.
>
> 2011/3/22 franki <franki at franki.eu.org>:
> > Hi,
> >
> > I'm building console application with several threads. So far I was
> > creating every object inside main() function and then I moved some of
> > them to their threads, and some stayed in main thread.
> > I have also installed handler for qDebug, qCritical and so one, inside
> > main() function like this:
> > qInstallMsgHandler(myMessageOutput);
> >
> > So now if I'm doing some heavy computing stuff inside object created in
> > main() function, every other thread waits for it, till it finishes, even
> > though they are in separate threads with signal/slot connection type
> > Qt::QueuedConnection.
> >
> > So I have two questions
> > 1. Should I do another class like "MyAppClass" and create myAppClass
> > object inside main() function, so the function main() would be much
> > cleaner, and then inside myAppClass object I would create other objects
> > and their threads, make signal/slot connection and so one.
> >
> > 2. Should I create myAppThread inside mian() function (or myAppClass
> > object) and move every other objects (that don't have their own thread
> > yet) to "myAppThread" so in that way I leave first thread entirely for
> > qtApplication. As I observed, when I do that, threads don't wait for each
> > other while they are using qDebug which is, as I assume, from
> > qtApplication thread. Also if I do explicitly sleep (which is wrong of
> > course) in some thread (not qtApplication thread) other threads don't
> > wait for that thread.
> >
> > So in simple words: is it worth of effort to:
> > 1. maintain clean main() function
> > 2. maintain mainthread only for qtApplication and rest of the objects
> > inside separate thread/threads
> >
> > best regards
> > Marek
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