QTcpSocket states on Windows and Linux



  • Hy,

    It seems that QTcpSocket behaves differently on different platforms. I don't understand something here or that's normal behavior ... I wrote this simple test class: (header file content is not pasted here)

    @#include "TcpSocketTester.h"

    TcpSocketTester::TcpSocketTester(QObject *parent) :
    QObject(parent)
    {
    connect(&_socket, SIGNAL(connected()), this, SLOT(socketConnected()));
    connect(&_socket, SIGNAL(error(QAbstractSocket::SocketError)),
    this, SLOT(socketError(QAbstractSocket::SocketError)));
    connect(&_socket, SIGNAL(disconnected()), this, SLOT(socketDisconnected()));
    connect(&_socket, SIGNAL(stateChanged(QAbstractSocket::SocketState)),
    this, SLOT(socketStateChanged(QAbstractSocket::SocketState)));

    _socket.connectToHost(QHostAddress("192.168.1.96"), 22154);
    

    }

    void TcpSocketTester::socketConnected()
    {
    qDebug() << QDateTime::currentDateTime().toString("hh:mm:ss.zzz") << ": CONNECTED";
    }

    void TcpSocketTester::socketError(QAbstractSocket::SocketError error)
    {
    qDebug() << QDateTime::currentDateTime().toString("hh:mm:ss.zzz") << ": SOCKET ERROR " << error;
    }

    void TcpSocketTester::socketDisconnected()
    {
    qDebug() << QDateTime::currentDateTime().toString("hh:mm:ss.zzz") << ": DISCONNECTED";
    }

    void TcpSocketTester::socketStateChanged(QAbstractSocket::SocketState state)
    {
    qDebug() << QDateTime::currentDateTime().toString("hh:mm:ss.zzz") << ": STATE " << state;
    }@

    IP address "192.168.1.96" that I try to connect to is not alive!!!

    This is output that I get under Ubuntu 10.04:

    "08:57:28.663" : STATE QAbstractSocket::HostLookupState
    "08:57:28.663" : STATE QAbstractSocket::ConnectingState
    "08:57:28.664" : STATE QAbstractSocket::ConnectedState
    "08:57:28.664" : CONNECTED
    "08:57:49.578" : SOCKET ERROR QAbstractSocket::RemoteHostClosedError
    "08:57:49.578" : STATE QAbstractSocket::ClosingState
    "08:57:49.578" : STATE QAbstractSocket::UnconnectedState
    "08:57:49.578" : DISCONNECTED

    This is output that I get under Windows XP:

    "09:13:17.546" : STATE QAbstractSocket::HostLookupState
    "09:13:17.546" : STATE QAbstractSocket::ConnectingState
    "09:13:59.546" : STATE QAbstractSocket::UnconnectedState
    "09:13:59.546" : SOCKET ERROR QAbstractSocket::NetworkError

    So it seems that under Linux socket signals that it is connected even if IP address is unreachable. Under Windows it seems to work as expected. But I had some cases under windows when it behaved the same way as in Linux, just didn't caught what was the reason.

    Maybe someone knows what is happening with these sockets??


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