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Creating a QApplication with Qt5.11.2 blocks for a short time any other QApplication running at Ubuntu



  • Last friday we decide upgrade from Qt5.9.6 to Qt5.11.2 at Ubuntu.
    Everything was running fine, until we notice that, when a new QApplication is created/instantied with "QApplication app(argc, argv);" any other Qt application running at the moment blocks for a very short time. It's really a very short time, but is enought
    to cause some frames dropped in our video application made in Qt. So, we decide to reduce our test, and made a simple
    application just for test, with a thread processing some job. We open a terminal and run this test. Then we open another
    terminal and run another instance, and again... at exactly this line "QApplication app(argc, argv);" the first application
    running blocks for a very short time. We tryed run 3 applications instance, and when we run the fourth, the others 3 apps
    blocks too together. In fact, we notice, that, if you open any QT application, blocks other QT Appplication. This happen
    only with Qt Applications. We get back to Qt5.9.6 and this problem dosen't happen anymore. Is there's some verification
    at QApplication instantiation that is causing this? It's a Bug? have anyone experienced this?


  • Moderators

    Sounds like a bug for sure. Please check the Qt bug tracker.


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