There a difference in your code. I guess it should not run this way, because the parameter lists are different.

rovshanb wrote:

1.     connect(nodePopulatorThread, SIGNAL(queryCompleted(DbTreeItemResult)), this, SLOT(nodeListAvailable(DbTreeItemResult)));
2.     nodePopulatorThread->start();
3. }

rovshanb wrote:

1. void DbTreeModel::nodeListAvailable(const DbTreeItemResult &result)

Otherwise you may adapt the parameter list of your slot method. if you are not using a const reference but a copy it should not be a problem.

If you adapt your connect statement to reflect the use as in your slot method, you are correct about worrying about the life time of your result.

Better not delete thread directly, it is very dangerous, use QObject::deleteLater(), which will post an event that will ultimately cause its deletion by the thread the object is living in.

There is a best practice wiki talking about details of good-to-use thread, of course deletion included:
http://developer.qt.nokia.com/wiki/Threads_Events_QObjects

I changed connect method to:

and moved delete statements to end of method.

But the slot was also firing with the above code (Qt Creator auto suggested it).

So when I write

Ok, thanks for the link, I’ll read it now

rovshanb wrote:

I changed connect method to:

1. connect(nodePopulatorThread, SIGNAL(queryCompleted(const DbTreeItemResult &)), this, SLOT(nodeListAvailable(const DbTreeItemResult &)));

and moved delete statements to end of method.

But the slot was also firing with the above code (Qt Creator auto suggested it).

So when I write

1. SLOT(nodeListAvailable(DbTreeItemResult))

and define slot as

1. DbTreeModel::nodeListAvailable(const DbTreeItemResult &result)

does it work differently than when specifying const & both in connect and slot?

I do not know. So far I believed that this will result in an error while connecting. Actually it did always give an error message to the console then and returned a false. However, could be just a conclusion on my side. When I did not receive a signal in a slot it was quite often a mismatch of the parameter lists.

Ok, thank you very much for helping!

You can also make your result item class as implicitly shared object http://doc.qt.nokia.com/4.7-snapshot/implicit-sharing.html [doc.qt.nokia.com] and then you can be sure that you don’t ‘lose’ your results.

In case someone has similar doubts as expressed above. There has been another thread started Signals/Slots behavior review [developer.qt.nokia.com] detailing the behaviour and the reasoning behind it.

rovshanb wrote:

But the slot was also firing with the above code (Qt Creator auto suggested it).

When the auto suggestions are changing parameter lists may be consiedered as a styling issue then.

Hi all,
I post my question in this thread to avoid a creation of a new topic.

I have a QObject class:

The problem is that I get some warning when I destroy the GestoreComunicazioneSatellite object.

I tryed some solution:

The only way to avoid warnings is:

but I’m not sure the m_thread is destroyed this way.

What do you think about?

… and what if I try:

?