if (_label) {
    delete _label;
    _label = 0;
}

delete _label;
_label = 0;

bool applicationIsRunning()
{
	bool ret = false;

	QString name( "first.exe" );
     
	HANDLE hProcessSnap = ::CreateToolhelp32Snapshot(TH32CS_SNAPPROCESS, 0); 

    if ( hProcessSnap == INVALID_HANDLE_VALUE ) 
        return false; 
 
    PROCESSENTRY32 pe32 = { 0 };
	pe32.dwSize = sizeof(PROCESSENTRY32); 

	if ( ::Process32First( hProcessSnap, &pe32 ) ) {
		do {
			if ( QString( pe32.szExeFile ).upper() == name.upper() ) {
				ret = true;
				break;
			}
		} 
		while (::Process32Next( hProcessSnap, &pe32 ) ); 
	}
     
	::CloseHandle( hProcessSnap ); 
    
	return ret; 
}

QSqlQueryModel *model = new QSqlQueryModel;
model->setQuery("SELECT name, salary FROM employee");
model->setHeaderData(0, Qt::Horizontal, tr("Name"));
model->setHeaderData(1, Qt::Horizontal, tr("Salary"));

QTableView *view = new QTableView;
view->setModel(model);
view->show();

QSortFilterProxyModel sortingModel;
sortingModel.setSourceModel(&model);

view.setModel(&sortingModel);
...
view.horizontalHeader()->setSortIndicator(1, Qt::AscendingOrder);
view.horizontalHeader()->setSortIndicatorShown(true);
view.horizontalHeader()->setClickable(true);
...