Memory leak? sysfer.dll access violation exception

[froeben]

Hello,

i have written a qml-map widget which gets displayed, but there seems to be an "undefined" object or something like that. I get an access violation exception from sysfer.dll.

I currently don't know where this comes from. Any help would be appreciated!

main.cpp

#include <QtWidgets/QApplication>
#include <MainWindow.h>
 
int main(int argc, char *argv[])
{
	QApplication a(argc, argv);
	// load resources from binary
	// infos: http://doc.qt.io/qt-5/resources.html
	Q_INIT_RESOURCE(qmlsources);
 
	MainWindow mw;
	mw.show();
 
	return a.exec();
}

#include <QtWidgets/QApplication>
#include <MainWindow.h>

int main(int argc, char *argv[])
{
	QApplication a(argc, argv);
	// load resources from binary
	// infos: http://doc.qt.io/qt-5/resources.html
	Q_INIT_RESOURCE(qmlsources);

	MainWindow mw;
	mw.show();

	return a.exec();
}

To copy to clipboard, switch view to plain text mode 

MainWindow.h:

#ifndef MAINWINDOW_H
#define MAINWINDOW_H
 
#include <QtWidgets/QWidget>
#include <QtWidgets/QMainWindow>
#include <QtWidgets/QPushButton>
#include <QtWidgets/QMenu>
#include <QtWidgets/QMenuBar>
#include <QtWidgets/QLabel>
 
class MainWindow : public  QMainWindow
{
	Q_OBJECT
 
public:
	MainWindow();
	~MainWindow();
 
protected:
	void contextMenuEvent(QContextMenuEvent *event) Q_DECL_OVERRIDE;
 
private slots:
	void quit();
 
private:
	QPushButton *_quit;
	QMenu *_fileMenu;
 
	QLabel *_infoLabel;
	QAction *_quitAct;
 
	void createMenus();
	void createActions();
 
 
};
 
#endif // MAINWINDOW_H

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QtWidgets/QWidget>
#include <QtWidgets/QMainWindow>
#include <QtWidgets/QPushButton>
#include <QtWidgets/QMenu>
#include <QtWidgets/QMenuBar>
#include <QtWidgets/QLabel>

class MainWindow : public  QMainWindow
{
	Q_OBJECT

public:
	MainWindow();
	~MainWindow();

protected:
	void contextMenuEvent(QContextMenuEvent *event) Q_DECL_OVERRIDE;

private slots:
	void quit();

private:
	QPushButton *_quit;
	QMenu *_fileMenu;
	
	QLabel *_infoLabel;
	QAction *_quitAct;

	void createMenus();
	void createActions();

	
};

#endif // MAINWINDOW_H

To copy to clipboard, switch view to plain text mode 

MainWindow.cpp:

#include <QDir>
 
#include <QtWidgets/QWidget>
#include <QtWidgets/QPushButton>
#include <QtWidgets/QMenu>
#include <QtWidgets/QMenuBar>
#include <QtWidgets/QLabel>
#include <QtWidgets/QBoxLayout>
#include <QtGui/QContextMenuEvent>
 
#include <QQmlEngine>
#include <QQmlComponent>
#include <QQuickView>
#include <QQuickWidget>
#include "MainWindow.h"
 
MainWindow::MainWindow() : QMainWindow ()
{
	// embed resources into binary
	// infos: http://doc.qt.io/qt-5/resources.html
	Q_INIT_RESOURCE(qmlsources);
 
	this->resize(1024, 768);
 
	createActions();
	createMenus();
 
	//WORKS!!!
	QQmlEngine *engine = new QQmlEngine(this);
	QQuickWidget *view = new QQuickWidget(engine, this);
	view->setSource(QUrl("qrc:/map.qml"));
 
	this->setCentralWidget(view);
	view->setResizeMode(QQuickWidget::SizeRootObjectToView);
}
 
MainWindow::~MainWindow()
{
 
}
 
void MainWindow::contextMenuEvent(QContextMenuEvent *event)
{
	QMenu menu(this);
	menu.addAction(_quitAct);
	menu.exec(event->globalPos());
}
 
void MainWindow::createMenus()
{
	_fileMenu = menuBar()->addMenu(tr("File"));
	_fileMenu -> addAction(_quitAct);
 
}
 
void MainWindow::createActions()
{
	_quitAct = new QAction(tr("Quit"), this);
	connect(_quitAct, &QAction::triggered, this, &MainWindow::quit);
 
}
 
void MainWindow::quit()
{
//	_infoLabel->setText(tr("Invoked <b>File|Quit</b>"));
	exit(1);
}

#include <QDir>

#include <QtWidgets/QWidget>
#include <QtWidgets/QPushButton>
#include <QtWidgets/QMenu>
#include <QtWidgets/QMenuBar>
#include <QtWidgets/QLabel>
#include <QtWidgets/QBoxLayout>
#include <QtGui/QContextMenuEvent>

#include <QQmlEngine>
#include <QQmlComponent>
#include <QQuickView>
#include <QQuickWidget>
#include "MainWindow.h"

MainWindow::MainWindow() : QMainWindow ()
{
	// embed resources into binary
	// infos: http://doc.qt.io/qt-5/resources.html
	Q_INIT_RESOURCE(qmlsources);

	this->resize(1024, 768);

	createActions();
	createMenus();

	//WORKS!!!
	QQmlEngine *engine = new QQmlEngine(this);
	QQuickWidget *view = new QQuickWidget(engine, this);
	view->setSource(QUrl("qrc:/map.qml"));

	this->setCentralWidget(view);
	view->setResizeMode(QQuickWidget::SizeRootObjectToView);
}

MainWindow::~MainWindow()
{

}

void MainWindow::contextMenuEvent(QContextMenuEvent *event)
{
	QMenu menu(this);
	menu.addAction(_quitAct);
	menu.exec(event->globalPos());
}

void MainWindow::createMenus()
{
	_fileMenu = menuBar()->addMenu(tr("File"));
	_fileMenu -> addAction(_quitAct);
	
}

void MainWindow::createActions()
{
	_quitAct = new QAction(tr("Quit"), this);
	connect(_quitAct, &QAction::triggered, this, &MainWindow::quit);
	
}

void MainWindow::quit()
{
//	_infoLabel->setText(tr("Invoked <b>File|Quit</b>"));
	exit(1);
}

To copy to clipboard, switch view to plain text mode 

map.qml:

import QtQuick 2.3
import QtPositioning 5.6
import QtLocation 5.6
 
Map {
	id: map
	width: 640
	height:480
 
	plugin: Plugin {
	name: "osm"
	}
 
	center {
		latitude: -27
		longitude: 153
	}
	zoomLevel: 10
	gesture.enabled: true
 
	Component.onCompleted: {
    console.log("Dimensions: ", width, height)
	}
}

import QtQuick 2.3
import QtPositioning 5.6
import QtLocation 5.6

Map {
	id: map
	width: 640
	height:480
	
	plugin: Plugin {
	name: "osm"
	}
	
	center {
		latitude: -27
		longitude: 153
	}
	zoomLevel: 10
	gesture.enabled: true

	Component.onCompleted: {
    console.log("Dimensions: ", width, height)
	}
}

To copy to clipboard, switch view to plain text mode 

Using VisualStudio2015 Ultimate, compiling as debug mode!

Thanks in advance for any hint or comment!

[ChrisW67]

I currently don't know where this comes from. Any help would be appreciated!

You are ahead of us... We don't even know what the error message was.

Run the program in your debugger and get a stack backtrace when it crashes. Read down the trace until you find the first line of your code that is mentioned.

[froeben]

Debugging is not possible since i don't have pdb files for sysfer.dll.

[ChrisW67]

Sysfer.dll is not your code, so the absence of the ability to debug it is largely irrelevant. Read down the backtrace until you reach the first line of your code that is mentioned. This is the trigggering event and the place to start working out what your code has done. In all likelihood you are trying to use a null, uninitialised, or invalid pointer.

[froeben]

I have found out, that the access violation happens when i use the scroll-wheel of my mouse.
I assume, that i need to re-implement the mouse events, because the scroll-functionality may lead to not getting new data within the OSM interface.

My stack trace only tells me, that the error happens in the external dll.
But right after using the scroll-wheel.

Any hint would be appreciated.