see if mdi child is already open

[ShapeShiftme]

Good day.
I am really new to QT development
I am currently opening a mdi chlld by the following means

web_view *child = new web_view;
    ui->mdi1->addSubWindow(child);
    //child->show();
    child->showMaximized();

web_view *child = new web_view;
    ui->mdi1->addSubWindow(child);
    //child->show();
    child->showMaximized();

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Now the above works great but the problem im having is that every time i click the button it opens a new window (child). How would i put something that says

if (window == open ) //will nee to code to see if it is open
{
reload child //Code to reload the child.
}
else
{
 web_view *child = new web_view;
 ui->mdi1->addSubWindow(child);
    child->showMaximized();
}

if (window == open ) //will nee to code to see if it is open
{
reload child //Code to reload the child.
}
else
{
 web_view *child = new web_view;
 ui->mdi1->addSubWindow(child);
    child->showMaximized();
}

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Help would be greatly appriciated

Regards