disable myself when clicked

[nifei]

connect( button, SIGNAL(clicked()), this, SLOT( on_button_clicked()));
 
This::on_button_clicked()
{
 button->setEnabled(false);
}

connect( button, SIGNAL(clicked()), this, SLOT( on_button_clicked()));

This::on_button_clicked()
{
 button->setEnabled(false);
}

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this does not work, of course. how to implement to disable a button when it is clicked?