qt popup window
/**
* You can use a QMessageBox like this:
* int output = QMessageBox::icon(this, tr("Title"), tr("content"),
* QMessageBox::button, QMessageBox::defaultButton);
*/
//for example :
int ret = QMessageBox::warning(this, tr("My Application"),
tr("The document has been modified.\n"
"Do you want to save your changes?"),
QMessageBox::Save | QMessageBox::Discard
| QMessageBox::Cancel,
QMessageBox::Save);