The QDialog class is the base class of dialog windows. ... QDialog  ( QWidget * parent=0, const char * name=0, bool modal=FALSE, WFlags f=0 )  . ... This enters a local event loop, which is terminated when the modal dialog calls done () (or accept () or reject ()). ... Calls reject () if it is a modal dialog, or accepts the close event if it is a modeless dialog. ... Shows the dialog box on the screen, as QWidget::show () and enters a local event loop if this dialog is modal (see constructor). ...