How to use an external variable ?

[Computer Hater]

Hi,

I want to make a couple of generic data fields program-wide available. I tried to pack them all into just a few global variables, but I don't see how I can get rid of a global variable altogether. Is there a better way ?
Or rather, is there a quick better way ? I just need to get this program functional for now.
Currently I'm using global extern variables like this:

data.h

#ifndef DATA_H
#define DATA_H
 
#include <QDebug>
 
class Dummy
{
public:
    Dummy()
    {
        qDebug() << "Dummy constructor";
    }
 
    void show()
    {
        qDebug() << "Dummy show";
    }
};
 
extern Dummy dummy;
 
#endif // DATA_H

#ifndef DATA_H
#define DATA_H

#include <QDebug>

class Dummy
{
public:
    Dummy()
    {
        qDebug() << "Dummy constructor";
    }

    void show()
    {
        qDebug() << "Dummy show";
    }
};

extern Dummy dummy;

#endif // DATA_H

To copy to clipboard, switch view to plain text mode 

data.cpp

#include "data.h"
 
Dummy dummy;  // alternate defintion 1

#include "data.h"

Dummy dummy;  // alternate defintion 1

To copy to clipboard, switch view to plain text mode 

main.cpp

#include "data.h"
 
Dummy dummy;  // alternate definition 2
 
int main(int argc, char *argv[])
{
    dummy.show();
 
    return 0;
}

#include "data.h"

Dummy dummy;  // alternate definition 2

int main(int argc, char *argv[])
{
    dummy.show();

    return 0;
}

To copy to clipboard, switch view to plain text mode 

The problem is that I wonder if the 'dummy' variable is actually ever initialized. The compiler doesn't complain, but neither of the qDebug() outputs is ever shown.
I tried putting the definition of the dummy variable in the data.cpp and the main.cpp files, respectively. But no effect.

However, if I put illegal code in the contrustor, the program does crash. (Though only if I put the definition of 'dummy' in 'data.cpp', not if it's in 'main.cpp'.)
So that suggests that the constructor is in fact called.

I may be just missing something very simple. But I can't conceive of it right now.

Thanks for any help.