The main idea is to have time shown on Qtable (is there a better class for it?) on main widget. At first the time is updated correctly every second, but after ~10 seconds the time is updated only every 2, 3, etc seconds. Now I think for some reason something makes the program slow down, and for that the clock is updated more infrequent. There may be some loop that i cant notice that continues to eat up the resources more and more after each update:

Qt Code: 
  1. class test : public QObject
  2. {
  3. Q_OBJECT
  4. public:
  5.    test(QWidget *qwi,QLabel *qlb);
  6.  
  7. public slots:
  8.    void	upd();
  9.  
  10. private:
  11.   QWidget *qw;
  12.   QLabel *ql;
  13. };
  14.  
  15. test::test(QWidget *qwi, QLabel *qlb)
  16. {
  17.    qw = qwi;
  18.    ql = qlb;
  19. }
  20.  
  21. void test::upd()
  22. {
  23.    QTimer *timer = new QTimer();
  24.    connect(timer,SIGNAL(timeout()),this,SLOT(upd())); 
  25.    timer->start(1000);
  26.    QTime time = QTime::currentTime();
  27.    QString str = "<font color='green'>";
  28.    str.append(time.toString("hh:mm:ss"));
  29.    str.append("</font>");
  30.    ql->setText(str);
  31.    qw->update();
  32. }
  33.  
  34.  
  35. int main (int argc, char *argv[])
  36. {
  37.     QApplication app(argc, argv);
  38.  
  39.     QWidget window;
  40.  
  41.     window.resize(1024, 768);
  42.     QLabel *timeLabel = new QLabel(&window);
  43.     timeLabel->setFrameStyle(QFrame::NoFrame | QFrame::Plain);
  44.     timeLabel->setFont(QFont("Times", 20, QFont::Bold));
  45.     timeLabel->setAlignment(Qt::AlignBottom | Qt::AlignRight);
  46.     QString str = "<font color='green'>";
  47.     QTime time = QTime::currentTime();
  48.     str.append(time.toString("hh:mm:ss"));
  49.     str.append("</font>");
  50.     timeLabel->setText(str);
  51.  
  52.     QPalette palette(QApplication::palette());
  53.     window.setParent(0,Qt::FramelessWindowHint);
  54.     palette.setColor(QPalette::Background, QColor("Black"));
  55.     QPushButton quit("Quit", &window);
  56.     quit.setFont(QFont("Times", 18, QFont::Bold));
  57.     palette.setColor(QPalette::Button, QColor("Blue"));
  58.     window.setPalette(palette);
  59.     quit.setPalette(palette);
  60.     quit.setGeometry(974, 0, 50, 20);
  61.     QObject::connect(&quit, SIGNAL(clicked()), &app, SLOT(quit()));
  62.  
  63.  
  64.     window.show();
  65.  
  66.     test *t = new test(&window,timeLabel);
  67.     t->upd();
  68.     return app.exec();
  69. }
  70.  
  71. #include "main.moc"
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