Why 6 threads for a simple app?

cmayer · wrote on 13 Oct 2011, 20:36

I was just wondering why there are 6 threads in task manager when running the simple widgets tutorial example. What are the other non UI threads doing? Is -QT- Qt making a new thread for each individual widget behind the scenes?

Running the release build of qt-tutorial-01 shows 131 handles and 6 threads, although these numbers fluctuate while the app is just sitting idle. Seems extremely inefficient, in addition to using up almost 11 MB of memory.

BTW - Do you intend to fix the compile errors? I mean really, in the first tutorial example???

(Now it's down to 3 threads, no wait, back up to 5 threads - what's going on in there?)

giesbert · wrote on 14 Oct 2011, 07:49

There are also OS threads, running in the apps.
E.g. on Windows, if COM is initialised (AFAIK Qt initialises COM on windows), there are COM threads running. Not each thread is a user created one.

By the way, which bugs do you mean? in "the docs page":http://doc.qt.nokia.com/4.7/widgets-tutorial.html it should work

cmayer · wrote on 14 Oct 2011, 16:09

Thanks for the info on threads.

The bugs are on the following URL.
http://developer.qt.nokia.com/wiki/Basic_Qt_Programming_Tutorial

Just 2 simple errors:
Line 18 of widget.h
Line 16 of widget.cpp

Easy to fix, but annoying for an absolute beginner.

koahnig · wrote on 14 Oct 2011, 16:44

[quote author="cmayer" date="1318608554"]
The bugs are on the following URL.
http://developer.qt.nokia.com/wiki/Basic_Qt_Programming_Tutorial

Just 2 simple errors:
Line 18 of widget.h
Line 16 of widget.cpp
[/quote]

I would assume that the extra ';' you are seeing there is due to a bug in devnet.
"See this thread":http://developer.qt.nokia.com/forums/viewthread/8336/
and "here is the bugreport on JIRA":https://bugreports.qt.nokia.com//browse/QTWEBSITE-264
On JIRA you can vote to raise the importance of this issue.

giesbert · wrote on 14 Oct 2011, 17:35

[quote author="cmayer" date="1318608554"]Thanks for the info on threads.
The bugs are on the following URL.
http://developer.qt.nokia.com/wiki/Basic_Qt_Programming_Tutorial
[/quote]

So, you aretalking about the wiki, not the docs :-)
The wiki acan even be edited by yourself...

giesbert · wrote on 14 Oct 2011, 17:38

[quote author="koahnig" date="1318610668"]
I would assume that the extra ';' you are seeing there is due to a bug in devnet.
"See this thread":http://developer.qt.nokia.com/forums/viewthread/8336/
and "here is the bugreport on JIRA":https://bugreports.qt.nokia.com//browse/QTWEBSITE-264
On JIRA you can vote to raise the importance of this issue. [/quote]

This bug seems to be fixed, I remove the semicolons and they stay away...

koahnig · wrote on 14 Oct 2011, 17:47

This is a test
@
void test ( double & tst );
connect(&tcpSocket, ... );
@

[quote author="Gerolf" date="1318613916"]This bug seems to be fixed, I remove the semicolons and they stay away...[/quote]
You seem to be right. Hopefully, it is fixed and not just vanished for some time. :-)

mgran · wrote on 14 Oct 2011, 18:16

[quote author="koahnig" date="1318614443"]
You seem to be right. Hopefully, it is fixed and not just vanished for some time. :-)
[/quote]

I wouldn't bet on it, the people running this place are not to be trusted! ;)

goetz · wrote on 14 Oct 2011, 21:58

[quote author="mariusg" date="1318616170"]
I wouldn't bet on it, the people running this place are not to be trusted! ;)[/quote]

Just feed them muffins, and they become handsome :-)