QNetworkAccessManager used by QTimer causes falling

[gibucsoft]

I am using QNetworkAccessManager in function, which is run periodically by QTimer. The code is:

QTimer* timer=new QTimer(this);
    connect(timer, SIGNAL(timeout()), this, SLOT(findUpdate()));
    timer->setSingleShot(false);
    timer->start(frequency*1800000);
 
void MainWindow::findUpdate()
{
    for (int i=0;i<aplikace.count();i++){
        QNetworkAccessManager* manager=new QNetworkAccessManager(this);
        connect(manager,SIGNAL(finished(QNetworkReply*)),this,SLOT(checkUpdate(QNetworkReply*)));
        manager->get(QNetworkRequest(QUrl("http://www.gibucsoft.8u.cz/"+lang+"gibuclauncher/verze.php?ver="+aplikace.at(i))));
   }
}

QTimer* timer=new QTimer(this);
    connect(timer, SIGNAL(timeout()), this, SLOT(findUpdate()));
    timer->setSingleShot(false);
    timer->start(frequency*1800000);

void MainWindow::findUpdate()
{
    for (int i=0;i<aplikace.count();i++){
        QNetworkAccessManager* manager=new QNetworkAccessManager(this);
        connect(manager,SIGNAL(finished(QNetworkReply*)),this,SLOT(checkUpdate(QNetworkReply*)));
        manager->get(QNetworkRequest(QUrl("http://www.gibucsoft.8u.cz/"+lang+"gibuclauncher/verze.php?ver="+aplikace.at(i))));
   }
}

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The compilation is fine and when I run my application from the Qt Creator it is OK as well but when I run it from the OS the program falls after a while (but not long enough for the timer to even start the function findUpdate). Sometimes before falling this error message shows:
This application has requested the Runtime to terminate it in an unusual way. Please contact the application's support team for more information.

[gibucsoft]

I already know the solution, the error was in creating a new QNetworkAccessManager each time. When I use only one, the application seems to work fine. But strange is, that in previous versions of my application it worked with multiple instances as well.

[anda_skoa]

Even a new QNetworkAccessManager should work, just very wasteful.

In any case the primary way to debug a crash is to look at the stack trace at the time of crash.

Cheers,
_