Blocking main thread, How?

[alizadeh91]

Hi all,
What are ways for blocking main thread?? I want to check for database connection in main thread before showing anything (e.g. mainwindow). There is some limitations:
I have a qml file which i show it before mainwindow and actually is my splash screen, i want to show database connection status on it so while blocking main thread, it have to be active and not blocked.
while blocking i want to run a thread to check database connection in interval ( the splash screen (qml file) is showing the progress).

the main.cpp is something like this:

int main(int argc, char *argv[])
{
    QApplication app(argc, argv);
    //-------------------------Load-SPLASH
    QQuickView splash;
    splash.setSource(QUrl("qrc:/qml/TSplashScreen.qml"));
    splash.show();
    app.processEvents();
 
     //Check if database is not connected
    TInitialDBConnectionCheck initializeDBCheck;
    if(!initializeDBCheck.isDBConnected())
    {
         //Here i have to block main thread and start a thread to check database status intevally. i know how to deal with second but i don't know how to block main thread to stay here while database is ready.
    }
 
    MainWindow mw;
    splash.close();
    mw.showFullScreen();
 
 
    return app.exec();
}

int main(int argc, char *argv[])
{
    QApplication app(argc, argv);
    //-------------------------Load-SPLASH
    QQuickView splash;
    splash.setSource(QUrl("qrc:/qml/TSplashScreen.qml"));
    splash.show();
    app.processEvents();

     //Check if database is not connected
    TInitialDBConnectionCheck initializeDBCheck;
    if(!initializeDBCheck.isDBConnected())
    {
         //Here i have to block main thread and start a thread to check database status intevally. i know how to deal with second but i don't know how to block main thread to stay here while database is ready.
    }

    MainWindow mw;
    splash.close();
    mw.showFullScreen();


    return app.exec();
}

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In addition there is a method called exec() in dialog that do whatever i want !!! but i have here a qml file and a mainthread and another custom thread!

[wysota]

QMutex, QWaitCondition. But then ask yourself whether you need it at all. Why not just move your extra thread logic into the main thread?

[alizadeh91]

Thanks,
I want to check database connection for every one second(if is disconnected) until connection established. So it seems it have to be done in a thread. That's right?

[wysota]

No, what does it change to have a thread here?

[alizadeh91]

so how to use a loop for every second in main thread?

[wysota]

It depends whether you can afford running an event loop or not. If yes, then use a timer, if no then use sleep().