qt popup window

1/** 
2 * You can use a QMessageBox like this:
3 * int output = QMessageBox::icon(this, tr("Title"), tr("content"),
4 *							  QMessageBox::button, QMessageBox::defaultButton);
5 */
6//for example :
7int ret = QMessageBox::warning(this, tr("My Application"),
8                               tr("The document has been modified.\n"
9                                  "Do you want to save your changes?"),
10                               QMessageBox::Save | QMessageBox::Discard
11                               | QMessageBox::Cancel,
12                               QMessageBox::Save);