How to delete modeless dialog?

[rajesh]

I want to create and show multiple dialog(or widget) on multiple user click.
so I written as:

void MainWindow::onIRSignalReport()
{
   ...
   SignalWindow *pSignalWindow = new SignalWindow();
   pSignalWindow->setSignalFile(fileName);
   pSignalWindow->show();
}

void MainWindow::onIRSignalReport()
{
   ...
   SignalWindow *pSignalWindow = new SignalWindow();
   pSignalWindow->setSignalFile(fileName);
   pSignalWindow->show();
}

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onIRSignalReport() getting called on menu item clicks.

lets user clicked multiple times and multiple SignalWindow is displayed.

if user close one of the user window then how I delete that pointer(pSignalWindow ) ?