Qt 4.8.7 memory artefacts

Paulll

I need to use Qt 4.8.7 for Embedded Linux to create a very simple project for testing.
Project includes 2 forms - Dialog (consists of QTextEdit and button. Button clears
QTextEdit and QClipboard) and MainWindow (consists of button that exec Dialog).

I edit text, copy part of it. Then clear editor and clipboard. I can't paste text after that,
but I dump memory using gcore and see text that I copied (several copies in html form).
What are these objects left in memory? Are these temporary objects or memory leaks?
Or I use something incorrectly.

My code:
mainwindow.h

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QMainWindow>

namespace Ui {
    class MainWindow;
}

class Dialog;

class MainWindow : public QMainWindow
{
    Q_OBJECT
public:
    MainWindow(QWidget * parent = 0);
    virtual ~MainWindow();

public slots:
    void slotOpenEditor();
    void slotDeleteEditor();

private:
    Ui::MainWindow * ui;
    Dialog * dlg;
};

#endif // MAINWINDOW_H

mainwindow.cpp

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include "widget.h"

MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent),
      ui( new Ui::MainWindow ),
      dlg( 0 )
{
    ui->setupUi(this);
    connect(ui->openEditor, SIGNAL(clicked()), this, SLOT(slotOpenEditor()));
}

MainWindow::~MainWindow()
{
    delete ui;

    delete dlg;
    dlg = 0;
}

void MainWindow::slotOpenEditor()
{
    dlg = new Dialog();
    connect(dlg, SIGNAL(finished(int)), this, SLOT(slotDeleteEditor()));
    dlg->exec();
}

void MainWindow::slotDeleteEditor()
{
    disconnect(dlg, SIGNAL(finished(int)), this, SLOT(slotDeleteEditor()));
    delete dlg;
    dlg = 0;
}

widget.h

#ifndef WIDGET_H
#define WIDGET_H

#include <QDialog>

namespace Ui {
    class Dialog;
}

class Dialog : public QDialog
{
    Q_OBJECT
public:
    Dialog(QWidget * parent = 0);
    virtual ~Dialog();
public slots:
    void slotCleanClipboard();
private:
    Ui::Dialog * ui;
};

#endif // WIDGET_H

widget.cpp

#include "widget.h"
#include "ui_Dialog.h"

#include <QDebug>
#include <QClipboard>
#include <QObject>

Dialog::Dialog(QWidget *parent)
    : QDialog(parent),
      ui( new Ui::Dialog )
{
    ui->setupUi(this);
    connect(ui->clearButton, SIGNAL(clicked()), this, SLOT(slotCleanClipboard()));
    connect(ui->clearButton, SIGNAL(clicked()), ui->textEdit, SLOT(clear()));
}

void Dialog::slotCleanClipboard()
{
    QApplication::clipboard()->clear();
}

Dialog::~Dialog()
{
    delete ui;
}

main.cpp

#include <QtGui>

#include "mainwindow.h"

int main(int argc, char** argv)
{
    QApplication app(argc, argv);
    MainWindow mainWindow;

    mainWindow.show();

    return app.exec();
}

Thanks for answers.

SGaist

Hi and welcome to devnet,

AFAIK, unless you specifically clean a memory region before releasing it, it will contain the "old data" until it gets overwritten.