problem in QAbstractSocket::SocketError

Hi everyone,
I am using qt 4.6.2. I am trying to use socket error for unplugging the network cable.I am using connect function to get the error.But when i removed the cable no error is occurring .

Code:

---

connect(clt,SIGNAL(error(QAbstractSocket::SocketError)),this,SLOT(connection_error(QAbstractSocket::SocketError)));
 
 
switch(err)
    {
    case 0:QMessageBox::critical(0,"connection error","The connection was refused by the peer (or timed out).",QMessageBox::Ok);
           break;
    case 2:QMessageBox::critical(0,"connection error","The host address was not found.",QMessageBox::Ok);
           break;
    case QAbstractSocket::NetworkError:QMessageBox::critical(0,"connection error","An error occurred with the network .",QMessageBox::Ok);
           break;
 
    case QAbstractSocket::RemoteHostClosedError:
           QMessageBox::critical(0,"connection error","disconnect .",QMessageBox::Ok);
           break;
    default:QMessageBox::critical(0,"connection error","undefine error.",QMessageBox::Ok);
        qDebug()<<"error is ......."<<err;
        break;
    }

---

Is there anything to do more ?

After remove network cable do you use any socket function?

I think if remove cable you receive stateChanged or disconnected signal. And receive error only if you do any socket operation after cable removing.

I have function for stateChanged and disconnected signal.But when i removed the cable no one is called.

ok. i try code and will tell later. But say me plz, what class is clt ?

And your OS plz.

.h

Code:

---

#ifndef MAINWINDOW_H
#define MAINWINDOW_H
 
#include <QMainWindow>
#include <QTcpSocket>
#include <QDateTime>
 
namespace Ui {
    class MainWindow;
}
 
class MainWindow : public QMainWindow
{
    Q_OBJECT
 
public:
    explicit MainWindow(QWidget *parent = 0);
    ~MainWindow();
 
private:
    QString statetoString(QAbstractSocket::SocketState);
 
private slots:
    void on_pushButton_clicked();
    void st_connected();
    void st_error(QAbstractSocket::SocketError);
    void st_stateChange(QAbstractSocket::SocketState);
    void st_disconnected();
 
    void on_pushButton_2_clicked();
 
private:
    Ui::MainWindow *ui;
    QTcpSocket *socket;
};
 
#endif // MAINWINDOW_H

---

.cpp

Code:

---

#include "mainwindow.h"
#include "ui_mainwindow.h"
 
MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);
    socket = new QTcpSocket();
    connect(socket,SIGNAL(connected()),this,SLOT(st_connected()));
    connect(socket,SIGNAL(error(QAbstractSocket::SocketError)),this,SLOT(st_error(QAbstractSocket::SocketError)));
    connect(socket,SIGNAL(disconnected()),this,SLOT(st_disconnected()));
    connect(socket,SIGNAL(stateChanged(QAbstractSocket::SocketState)),this,SLOT(st_stateChange(QAbstractSocket::SocketState)));
}
 
MainWindow::~MainWindow()
{
    delete ui;
    delete socket;
}
 
void MainWindow::on_pushButton_clicked()
{
    socket->connectToHost("adsl.by", 80);
}
 
void MainWindow::st_connected()
{
    ui->textEdit->append("Connected at " + QDateTime::currentDateTime().toString("hh:mm:ss dd.MM.yyyy"));
}
 
void MainWindow::st_disconnected()
{
    ui->textEdit->append("Disconnected at " + QDateTime::currentDateTime().toString("hh:mm:ss dd.MM.yyyy"));
}
 
void MainWindow::st_error(QAbstractSocket::SocketError socketError)
{
    ui->textEdit->append("Error " + socket->errorString() + " at " + QDateTime::currentDateTime().toString("hh:mm:ss dd.MM.yyyy"));
}
 
void MainWindow::st_stateChange(QAbstractSocket::SocketState socketState)
{
    ui->textEdit->append("State change to " + statetoString(socketState) + " at " + QDateTime::currentDateTime().toString("hh:mm:ss dd.MM.yyyy"));
}
 
void MainWindow::on_pushButton_2_clicked()
{
    if(socket->isOpen())
        socket->disconnectFromHost();
}
 
QString MainWindow::statetoString(QAbstractSocket::SocketState socketState)
{
    QString statestring;
    switch(socketState)
    {
        case QAbstractSocket::UnconnectedState : statestring="the socket is not connected";
            break;
        case QAbstractSocket::HostLookupState : statestring="the socket is performing a host name lookup";
            break;
        case QAbstractSocket::ConnectingState : statestring="the socket has started establishing a connection";
            break;
        case QAbstractSocket::ConnectedState : statestring="a connection is established";
            break;
        case QAbstractSocket::BoundState : statestring="the socket is bound to an address and port";
            break;
        case QAbstractSocket::ClosingState : statestring="the socket is about to close";
            break;
        case QAbstractSocket::ListeningState : statestring="listening state";
            break;
        default: statestring="unknown state";
    }
    return statestring;
}

---

i'm coded and have next result when remove cable after connect button clicked

Code:

---

State change to the socket is performing a host name lookup at 21:42:39 11.03.2011
State change to the socket has started establishing a connection at 21:42:40 11.03.2011
State change to a connection is established at 21:42:40 11.03.2011
Connected at 21:42:40 11.03.2011
Error The remote host closed the connection at 21:42:51 11.03.2011
State change to the socket is about to close at 21:42:51 11.03.2011
State change to the socket is not connected at 21:42:51 11.03.2011
Disconnected at 21:42:51 11.03.2011

---

Thanks for reply .But the above code is not working for me when i removed the cable.
I am using fedora 11 (64bit linux kernel 2.6.29) .The clt is a object of client class which inherits QTcpSocket class.

Maybe it's platform specific or network card driver problem.

If you want known interface state try use QNetworkConfiguration

Quote:

---

Originally Posted by sattu

Hi everyone,
I am using qt 4.6.2. I am trying to use socket error for unplugging the network cable.I am using connect function to get the error.But when i removed the cable no error is occurring .
Is there anything to do more ?

---

http://doc.trolltech.com/latest/qnet....html#isOnline

QNetworkConfigurationManager class was introduced in Qt 4.7.But i am using 4.6.2.So how can i add this class in my qt application ?

Do you can use 4.7.2 ?

I tried the program in qt 4.7 (os xp2) and it is working fine.I think there is some problem in qt4.6.2
thanks