On Freitag, 1. April 2022 15:17:59 CEST Michael Jackson wrote: > I have a bit of code where in I am removing a QWidget from the UI and it > needs to be truly cleaned up as its parent QObject is also being cleaned > up. I thought I did the appropriate: > > layout->removeWidget(widget); > widget->setParent(nullptr); > widget->deleteLater(); > > I put a "std::cout <<... " in the widget's destructor but I never see it > printed. I put a break point in the destructor and the break point never > gets hit. Looked around on the internet, various forums, double checked > that the event loop is actually running, called > qtapp->eventLoop()->processEvents() (or whatever that bit of code is) a few > times. Nothing. Currently we are leaking memory because we are creating the > widget but never deleting the widget when it is removed from the UI. I'll > assume since I have complete control of the UI that the event loop is > running. The last line in our main() is app.exec(); so I am assuming the > event loop is running. This was originally with a self-built Qt 5.15.2 on > macOS 10.15 (Catalina) but I installed the normal Qt 5.15.2 from www.qt.io > and it behaves the same way. I have other applications where this does > actually work so I am trying to figure out where in this new version of the > application we messed up. If anyone has any thoughts on where to look I > would really appreciate the sanity check. > > If we are in the middle of a signal being fired would that stop the > deleteLater() from working? Do I need to manually disconnect all > signals/slots for deleteLater() to work? We have a mix of new style > connects and old style connects? Is that messing with deleteLater()? -- > Mike Jackson > > You have to make sure the event loop is running on the thread owning the QObject. Do you have more than one thread?
And remember that std::cout needs a std::endl to flush and print anything. I normally use qDebug() or qWarning() instead as a safer logging tool, since I often forget the std::endl myself. Best regards Allan _______________________________________________ Interest mailing list Interest@qt-project.org https://lists.qt-project.org/listinfo/interest
