Gui hangs when close button is clicked

[Tanny007]

Hello,
I am a newbie in Qt.I would like to close a window but the Qt Gui hangs when I do so.
I am trying to close the Gui with this->close()

connect(ui->Close, SIGNAL(clicked()), this, SLOT(close()));

connect(ui->Close, SIGNAL(clicked()), this, SLOT(close()));

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void MainWindow::close()
{
    this->close();
}

void MainWindow::close()
{
    this->close();
}

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Can anybody tell me how to close the Gui without hanging it.