Creating an object of QGraphicsScene results in segmentation fault

[TheIndependentAquarius]

I created a new Qt 5 project with QtCreator, and added the following lines to it.

#include <QGraphicsScene>

// in main():
QGraphicsScene scene;

In the .pro file I added:
Qt += gui

The object creation of QGraphicsScene is resulting in the segmentation fault. What point am I missing?

[ChrisW67]

This works without issue Qt 5.2, GCC 4.7 on Linux:

#include <QApplication>
#include <QGraphicsScene>
 
int main(int argc, char **argv) {
    QApplication app(argc, argv);
    QGraphicsScene scene;
    return 0;
}

#include <QApplication>
#include <QGraphicsScene>

int main(int argc, char **argv) {
    QApplication app(argc, argv);
    QGraphicsScene scene;
    return 0;
}

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The QApplication must exist before the scene or it seg faults here too.

[TheIndependentAquarius]

Thanks for respondng.


I realized now that instead of QApplication my rest of the program is using QtGui/QGuiApplication.

How to use QGraphicsScene with QtGui/QGuiApplication?

[ChrisW67]

You can't. QGraphicsScene is part of QtWidgets and intimately connected to a full QApplication instance.

[anda_skoa]

And you will also need

QT += widgets

QT += widgets

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to add the widget library

Cheers,
_