Function call missing argument list to create pointer

Question

I tried to connect my app to OpenViBE through VRPN server. My app works well until I try to add code to connect my app to VRPN server.

My code looks like this:

MainWindow.c code:

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <QtUiTools/QUiLoader>
#include <QFile>
#include <QMessageBox>
#include <QFileDialog>

#include <iostream>
using namespace std;

#include "vrpn_Analog.h"

MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);

    currentImage = 0;
    labelSize = ui->label_2->size();

    createActions();
    openFileDialog();
}
void MainWindow::checkChannels()
{
    vrpn_Analog_Remote *vrpnAnalog = new vrpn_Analog_Remote("Mouse0@localhost");
    vrpnAnalog->register_change_handler( 0, handle_analog );
}


void VRPN_CALLBACK MainWindow::handle_analog( void* userData, const vrpn_ANALOGCB a )
{
 int nbChannels = a.num_channel;

 cout << "Analog : ";

 for( int i=0; i < a.num_channel; i++ )
 {
 cout << a.channel[i] << " ";
 }

 cout << endl;
}

MainWindow.h code:

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QMainWindow>
#include <QFileInfoList>

#include "vrpn_Analog.h"

namespace Ui {
class MainWindow;
}

class MainWindow : public QMainWindow
{
    Q_OBJECT

public:
    explicit MainWindow(QWidget *parent = 0);
    ~MainWindow();

protected:
    void resizeEvent(QResizeEvent *);

private slots:
    void openFileDialog();    

private:    
    void checkChannels();

    void VRPN_CALLBACK handle_analog( void* userData, const vrpn_ANALOGCB a );

};

#endif // MAINWINDOW_H

With this code, when I try to run my app I get:

error: C3867: 'MainWindow::handle_analog': function call missing argument list; use '&MainWindow::handle_analog' to create a pointer to member

I try to edit code by error advice, but I get another error:

error: C2664: 'vrpn_Analog_Remote::register_change_handler' : cannot convert parameter 2 from 'void (__stdcall MainWindow::* )(void *,const vrpn_ANALOGCB)' to 'vrpn_ANALOGCHANGEHANDLER'
There is no context in which this conversion is possible

I search around, but I don't find any usable solution.

Methods checkChannels and handle_analog I "copy" from this code, where all works fine:

#include <QtCore/QCoreApplication>
#include <iostream>
#include "vrpn_Analog.h"


void VRPN_CALLBACK vrpn_analog_callback(void* user_data, vrpn_ANALOGCB analog)
{
    for (int i = 0; i < analog.num_channel; i++)
    {
        if (analog.channel[i] > 0)
        {

            std::cout << "Analog Channel : " << i << " / Analog Value : " << analog.channel[i] << std::endl;
        }
    }
}

int main(int argc, char *argv[])
{
    QCoreApplication a(argc, argv);

    /* flag used to stop the program execution */
    bool running = true;

    /* VRPN Analog object */
    vrpn_Analog_Remote* VRPNAnalog;

    /* Binding of the VRPN Analog to a callback */
    VRPNAnalog = new vrpn_Analog_Remote("openvibe_vrpn_analog@localhost");
    VRPNAnalog->register_change_handler(NULL, vrpn_analog_callback);

    /* The main loop of the program, each VRPN object must be called in order to process data */
    while (running)
    {
        VRPNAnalog->mainloop();
    }

    return 0;

    return a.exec();
}

Where I'm doing mistake? Thanks for all replies.

Answer 1

I had a similar error in Visual Studio: "function call missing argument list; use '&className::functionName' to create a pointer to member"..

I was just missing the parenthesis when calling the getter, so className.get_variable_a()