I see this comments //! [0]
very often in Qt examples. What they mean?
Example (from a default MDI example):
//! [0]
exitAct = new QAction(tr("E&xit"), this);
exitAct->setShortcuts(QKeySequence::Quit);
exitAct->setStatusTip(tr("Exit the application"));
connect(exitAct, SIGNAL(triggered()), qApp, SLOT(closeAllWindows()));
//! [0]