SIGNAL and SLOT parameters issue in QT - c++

Question

Could someone please advise how to correctly implement SLOT execution?
my code:
prog::prog(QWidget *parent): QMainWindow(parent) //constructor (VisualStudio):
{
ui.setupUi(this);
QCustomPlot * customPlot = new QCustomPlot(this);
setupRealtimeDataDemo(customPlot);
// + more code
}
void prog::setupRealtimeDataDemo(QCustomPlot * customPlot)
{
customPlot->addGraph(); //
// + more related with graph methods
// setup a timer that repeatedly calls realtimeDataSlot:
connect(&dataTimer, SIGNAL(timeout()), this, SLOT(realtimeDataSlot(QCustomPlot)));
dataTimer.start(0); // Interval 0 means to refresh as fast as possible
}
void prog::realtimeDataSlot(QCustomPlot *customPlot)
{
// calculate two new data points:
#if QT_VERSION < QT_VERSION_CHECK(4, 7, 0)
double key = 0;
#else
double key = QDateTime::currentDateTime().toMSecsSinceEpoch()/1000.0;
#endif
static double lastPointKey = 0;
if (key-lastPointKey > 0.01) // at most add point every 10 ms
{
double value0 = qSin(key); //sin(key*1.6+cos(key*1.7)*2)*10 + sin(key*1.2+0.56)*20 + 26;
double value1 = qCos(key); //sin(key*1.3+cos(key*1.2)*1.2)*7 + sin(key*0.9+0.26)*24 + 26
// add data to lines:
customPlot->graph(0)->addData(key, value0);
customPlot->graph(1)->addData(key, value1);
// + more code related with graph
}
}
Here are my findings:
SIGNAL and SLOT need the same signature, build program won't run
SLOT ( because SLOT become undefined).
Possible solution: remove QCustomPlot argument form SLOT, but how
then should I send to realtimeDataSlot pointer to QCustomPlot? Maybe
it possible to overload timeout() ? Maybe other solution?
I discovered when I use #include "winsock2.h" and try to "Promote to..." option
like in http://www.qcustomplot.com/index.php/tutorials/settingup errors
appears about parameters redefinition , so this workaround I cannot
use. I also don't won't to use qwt
Thanks is advance for help!

Answer 1

There is a multitude of solutions. Two come to mind:
Make the QCustomPlot* a member of the prog class:
class prog : public QWidget {
Q_OBJECT
QScopedPointer<QCustomPlot> m_plot;
...
}
prog::prog(QWidget *parent): QMainWindow(parent) :
m_plot(new QCustomPlot)
{
ui.setupUi(this);
setupRealtimeDataDemo(m_plot.data());
}
Use C++11 and Qt 5 features:
connect(&dataTimer, &QTimer::timeout, this, [=]{
realtimeDataSlot(customPlot); // doesn't need to be a slot anymore
});