Russian Qt Forum

class FORM: public QWidget
{
  Q_OBJECT
public:
  QPushButton *b_start;
  CANCEL_BTN *b_cancel;
  volatile int *flag_stop;
   ~FORM();
  FORM(QWidget *parent);
public slots:
  void on_b_start_clicked();
};

...

void FORM::on_b_start_clicked()
{
  int sch = 0;

  *flag_stop = false;

  b_start->setEnabled(false);

  b_cancel->show();

  QCoreApplication::processEvents(QEventLoop::AllEvents );

  //pthread_create(&ar_theread_handle,0, on_b_start_clicked_theread, this);
  QCoreApplication::processEvents(QEventLoop::AllEvents );

  while (!(*flag_stop))
    {
      Sleep(1000); //Тут длительная операция
      sch++;
      QCoreApplication::processEvents(QEventLoop::AllEvents );
      if (sch >10)
        break;
    }

  *flag_stop = true;

  //while (!pthread_join(ar_theread_handle,0));
  ar_theread_handle = 0;

  b_start->setEnabled(true);
}

class CANCEL_BTN: public QDialog
{
  Q_OBJECT
public:
  volatile int *flag_stop;
  QPushButton *b_stop;
  ~CANCEL_BTN();
  CANCEL_BTN(volatile int *flag_);
public slots:
  void on_b_stop_clicked();
};

void FORM::on_exit()
{
  *flag_stop = true; 
}

void FORM::on_b_start_clicked()
{
  QProgressDialog progress("Executing...", "Abort", 0, 0, 0);
  progress.setSizeGripEnabled ( 0 );
  progress.setWindowModality(Qt::WindowModal);
   
  QObject::connect(&progress, SIGNAL( canceled() ), this, SLOT(on_exit()));
  progress.show();
   
  int sch = 0;

  *flag_stop = false;

  //Длительная операция которую нужно отменить
  while (!(*flag_stop))
    {
      Sleep(1000);
      sch++;
      //QCoreApplication::processEvents(QEventLoop::AllEvents );
      if (sch >10)
        break;
    }
	
  *flag_stop = true;
}