Qt & Memory Leak

[fanoI]

@anda_skoa

Our application is really complex as it is a sort of Distributed Process, there is a master process that for you is "The Application" that forks a lot of children: the Gui, the Manager, the Storage, Drivers and so on... We have tried to use Valgrind but it stopped on the first fork

On a real "OS" as Windows or Mac OSX would be really easy to find a problem as this as we would have a real debugger, but on Linux?

That's correct.

OK, so we are doing the right thing!

I observed some issues when used QtWebKit Bridge.

Well this a good and bad news at the same time! I really suspected this...
So QtWebKit Bridge is bugged and cannot be used on production? How I could say this to my PM, now?

Did you provide parent for QMovie?

Yes I've created a QLabel in my MessageBox (that is I've passed 'this' to it) where normally it is the icon, then I've created a QMovie as son of the QLabel and called the QMovie's method to start the animation... well when the MessageBox is closed we noted that a timer was continuing to run! In the end we have called "stop" in our QMessageBox implementation destructor, but if I delete the QMovie the application crashes so, the object is destroyed by Qt, but the Movie is not stopped! I see this as a bug or at least bad design on the Qt side

Well, the version of Qt you are using seems to be old enough. Did you try to use 4.8.5 or Qt5?

The problem is that the OS we use is really old and we cannot update it as my PM says: "if it works don't fix it!", the problem is that "It don't work and I need to fix it!", the native Qt version was 3! To install Qt 4.6 we needed to create the RPMs ourselves!

By the way if no solution arises I'll try to convince them that update is necessary at least to Qt 4.8.5, for Qt 5 myself fear to much incompatibilities to be honest
The problem will be to found the RPMs... oh well we have compiled it one time, we recompile them again... if only we had time, we are in retard in the schedule... again!

As, for memory leaks in Qt - since it uses lazy deletion of objects some profiling tools can count this as leaks.

OK, but this is Linux itself that sees the Memory Leaks and kills the application! If you use the Linux top command and make run the software with a simulator you see 2 MB on any iterations are lost... after 12 Hours the application is dead and in /var/log/messages you see "xxx killed by Out Of Memory Killer". If Linux thinks that "lazy deletion of objects" is lost memory... well what we could do?

Thanks for the help, it is really appreciated!
Let me know if you have other ideas