runtime error: â€œ*** glibc detected ***: double free or corruption (out)â€

I have interesting combination of warnings & errors.

Firstly, when debugging, i get warnings:

Code:

can't find linker symbol for virtual table for `QFile' value
  found `WebCore::JSDocument::JSDocument(JSC::Structure*, WebCore::JSDOMGlobalObject*, WTF::PassRefPtr<WebCore::Document>)' instead
RTTI symbol not found for class 'WebCore::JSHTMLDocument'
RTTI symbol not found for class 'WebCore::JSHTMLDocument'
RTTI symbol not found for class 'WebCore::JSHTMLDocument'

secondly, i have runtime error:

Code:

QIODevice::open: File access not specified

and momently

Code:

*** glibc detected *** <path>: double free or corruption (out): 0x081f9d00 ***

Here's the minimal code that causes that errors:

Files

In result folder created folder "resources" and in it file "vk.cookie" (everything without quotes).

Bug.pro

Code:

QT       += core gui webkit network xml
 
TARGET = Bug
TEMPLATE = app
 
 
SOURCES += main.cpp \
    api_vk.cpp \
    printer.cpp
 
HEADERS  += \
    api_vk.h \
    printer.h

main.cpp

Code:

#include <QtGui/QApplication>
#include "api_vk.h"
#include "printer.h"
 
int main(int argc, char *argv[]) {
    QApplication a(argc, argv);
    API_VK *apivk = new API_VK;
    apivk->authorise();
    Printer *printer = new Printer;
    QObject::connect(apivk, SIGNAL(authorisationSucceed()), printer, SLOT(printOK()));
    QObject::connect(apivk, SIGNAL(authorisationFailed(QString,QString)), printer, SLOT(printFail()));
 
    return a.exec();
}

api_vk.h

Code:

#ifndef API_VK_H
#define API_VK_H
 
#include <QObject>
#include <QTimer>
#include <QUrl>
#include <QtNetwork/QNetworkCookieJar>
 
class QWebView;
class QString;
class QNetworkReply;
class QXmlInputSource;
class QTimer;
class QNetworkCookie;
 
class API_VK : public QObject
{
    Q_OBJECT
public:
    explicit API_VK(QObject *parent = 0);
 
signals:
    void authorisationFailed(QString error, QString error_description);
    void authorisationSucceed();
 
public slots:
    void authorise();
 
protected:
    void readCookies();
    void writeCookies();
 
protected slots:
    void newAuthoriseRequest();
    void processUrl(QUrl url);
 
private:
    static const QString app_id;
    static QString access_token;
    static qint32 expires_in;
    QWebView *messagesPage;
    QList<QNetworkCookie> cookies;
    QNetworkCookieJar jar;
 
    static bool authorised;
};
 
#endif

api_vk.cpp

Code:

#include "api_vk.h"
#include <QtGui>
#include <QWebView>
#include <QtNetwork/QNetworkRequest>
#include <QtNetwork/QNetworkAccessManager>
#include <QtNetwork/QNetworkReply>
#include <QtNetwork/QNetworkCookie>
#include <QtNetwork/QNetworkCookieJar>
#include <QString>
#include <QStringList>
#include <QFile>
#include <QTextStream>
#include <QTimer>
#include <QUrl>
#include <QtXml>
#include <QVariant>
#include <QDateTime>
#include <QDebug>
 
 
bool API_VK::authorised = false;
const QString API_VK::app_id = "2783286";
QString API_VK::access_token = "";
int API_VK::expires_in = 0;
 
 
    // defining class methods
 
API_VK::API_VK(QObject *parent) :
    QObject(parent)
{
}
 
void API_VK::authorise() {
    newAuthoriseRequest();    // 1. going here
}
 
void API_VK::newAuthoriseRequest() {
    // gets new access_token
    // 2. going here
 
    messagesPage = new QWebView;
    readCookies();
    jar.setCookiesFromUrl(cookies, QUrl("http://vk.com"));
    messagesPage->page()->networkAccessManager()->setCookieJar(&jar);
 
    QUrl url("http://oauth.vk.com/authorize");
    url.addQueryItem("client_id", app_id);
    url.addQueryItem("scope", "messages");
    url.addQueryItem("redirect_uri","http://api.vk.com/blank.html");
    url.addQueryItem("display","page");
    url.addQueryItem("response_type","token");
 
    messagesPage->load(QNetworkRequest(url));
    connect(messagesPage, SIGNAL(urlChanged(QUrl)), this, SLOT(processUrl(QUrl)));
    messagesPage->show();
 
}
 
void API_VK::processUrl(QUrl url) {  // 3. going here
/* firstly we're here when oath.vk.com redirects us to api.vk.com/login...
 * in this case we're exiting at 4.
 * secondly, user logs in, and api.vk.com/login redirects us back to oath.vk.com,
 * where we get access_token, etc
 * and when debugging, we start receiving warnings about "can't find linker symbol" secondly, not firstly
 */
 
//    if (!url.hasQueryItem("access_token"))
//        return;
 
    /* I commented previous part because most of you doesn't have VK accounts so you can't go
     * to the next part of code */
 
    access_token = url.queryItemValue("access_token");
    expires_in = url.queryItemValue("expires_in").toInt();
 
    emit authorisationSucceed();
 
    authorised = true;
    cookies = messagesPage->page()->networkAccessManager()->cookieJar()->cookiesForUrl(QUrl("http://vk.com"));
    messagesPage->deleteLater();
    writeCookies();
}
 
void API_VK::readCookies() {
    QFile file("./resouces/vk.cookie");
    if (!file.open(QIODevice::ReadOnly | QIODevice::Text)) {
        return;
    }
 
    QTextStream in(&file);
    QByteArray name, value;
    while (!in.atEnd()) {
        in >> name >> value;
        cookies.append(QNetworkCookie(name, value));
    }
}
 
void API_VK::writeCookies() {
    QFile file("./resouces/vk.cookie");   // note: this file exists
    if (!file.open(QIODevice::Truncate | QIODevice::Text)) {  // 5. at this line i receive runtime errors
        return;
    }
 
    QTextStream out(&file);
    for (QList<QNetworkCookie>::const_iterator i = cookies.begin(); i != cookies.end(); ++i) {
        out << (*i).name() << ' ' << (*i).value() << '\n';
    }
}

printer.h

Code:

#ifndef PRINTER_H
#define PRINTER_H
 
#include <QObject>
#include <QDebug>
 
struct Printer: public QObject {
    Q_OBJECT
 
public slots:
    void printOK() { qDebug() << "OK"; }
    void printFail() { qDebug() << "Fail"; }
};
 
#endif // PRINTER_H

printer.cpp

Code:

#include "printer.h"

Here's the full output with memory dump: http://pastebin.com/btVNe4nd

At 5 QtCreator says that app received signal from OS (signal: SIGABRT) and decompiles

Code:

Disassembler (__kernel_vsyscall)
 
0x132414  <+0x0000>         int    $0x80
0x132416  <+0x0002>         ret

And valgrind says:

Code:

Analysis of memory <path>
QMetaObject::connectSlotsByName: No matching signal for on_cancelButton_clicked()
"sni-qt/23102" WARN  20:28:53.697 void StatusNotifierItemFactory::connectToSnw() Invalid interface to SNW_SERVICE 
** Analysis finished **
** Unknown error **

Question on StackOwerflow: http://stackoverflow.com/questions/1...corruption-out

So, why I receive they? I don't use malloc()/free(), you can see it.

runtime error: â€œ*** glibc detected ***: double free or corruption (out)â€

runtime error: â€œ* glibc detected *: double free or corruption (out)â€