Hi,

• Qt Undefined Reference To Vtable
• Qt Undefined Reference To Signal
• Qt Undefined Reference To Class
• Undefined Reference To Main

thank you already for investing time to help me finding a solution to my problem. I did research on the web and did not find any idea how to handle my errors. I do voluntary work for a youth organization and I try to help them out with making a program for easier handling with all the finance things. Since we do not have any programmer in our organization I try to deeper my knowledge and ofcourse help the group. I do have basic knowledge in C/C++.

@Dong Are you linking against that library? You get such errors if you forget to link against a library containing the reference. If your corresponding slot has a use for it (example: mySlot(bool isToggled)) this value will be passed to it. In your example, however, the clicked signal does not come with any parameter - so it will not pass any data to doSomething(double.pointer) - and in truth, MOC will not allow such a connection (again - see the documentation, it's. Qt Slots Undefined Reference by making comments and posts, participating in competitions and more. We're Checking 150+ Casinos To Find The Perfect One For You. If I’m about to modify a slot function I might take an extra minute to look around since most IDEs can’t tell syntactically where it’s used in a SLOT macro. In this case you have to search for it textually.) Thanks to C11 lambdas and Qt’s ongoing evolution, these short slots can be replaced by a more succinct syntax. Qt's widgets have many pre-defined slots, but it is common practice to subclass widgets and add your own slots so that you can handle the signals that you are interested in. The signals and slots mechanism is type safe: The signature of a signal must match the signature of the receiving slot.

I try to make a GUI with which it is possible and easy!( by clicking buttons and filling in gaps) to save a new payment and later (at the end of the year) make a financial report. I wanted to use structs with IDs for every payment. The IDs should link every payment to a project and pay office. I know it is a lot of text for you to read and any kind of idea how to better my concept and my existing problems would help me to better the final product. All in all it should in the end make a nice Excel table for our chairmain.

I did start with this code, trying to make just one button (signal slot) work and the errors appeared when building.
The errors are in the pushbutton.cpp, line 3 and 18.
C:QtTools...pushbutton.cpp:3: Fehler:undefined reference to `vtable for pushbutton'

Qt Undefined Reference To Vtable

C:QtTools...pushbutton.cpp:18: Fehler:undefined reference to `vtable for pushbutton'

collect2.exe:-1: Fehler:error: ld returned 1 exit status

headers:
-mainwindow.h
-pushbutton.h
sourcecode:
-main.cpp
-mainwindow.cpp
-pushbutton.cpp

@#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QMainWindow>

namespace Ui {
class MainWindow;
}

class MainWindow : public QMainWindow
{
Q_OBJECT

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

private:
Ui::MainWindow *ui;
};

#endif // MAINWINDOW_H
@

@#ifndef PUSHBUTTON_H
#define PUSHBUTTON_H
#include <QObject>
#include <QString>

class pushbutton : public QObject
{
Q_OBJECT

public:
pushbutton(QObject *parent = 0);
~pushbutton();

//public slots:
//void setValue(int value);

//signals:
//void valueChanged(int newValue);

//private:

};

#endif // pushbutton_H
@

@#include 'mainwindow.h'
#include 'pushbutton.h'

#include <QApplication>

int main(int argc, char *argv[])
{
QApplication a(argc, argv);
MainWindow w;
w.show();
//pushbutton cPus;
//------------------------------
struct structId{
int iIDa;
int iIDb;
int iIDc;
char sIDa[50];
char sIDb[50];
char sIDc[50];
int ivalue;
}StructFirst;

}
@

@#include 'mainwindow.h'
#include 'ui_mainwindow.h'

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

MainWindow::~MainWindow()
{
delete ui;
}
@

@#include 'pushbutton.h'

*pushbutton::pushbutton(QObject parent):QObject(parent)
{
//createID();
//Variablen

Qt Undefined Reference To Signal

}
void pushbutton::createID()
{
int iIda = 0;
int iIdb = 0;
int iIdc = 0;

}
pushbutton::~pushbutton()
{

Qt Undefined Reference To Class

}

Undefined Reference To Main

@