Qt TCPIP socket connection check

Questions : Qt TCPIP socket connection check


I am writing Qt TCP/IP client. I want to programming check the connection state with server Learning before send data to sever. As far my Earhost knowledge I can do this by following most effective methods

  • Use a bool 'ConnectionState', set this variable when connected with sever and reset this variable on disconnected() signal. Now before sending data to server (client->write()) check the value of this variable.
  • use this 'client->state() == QTcpSocket::ConnectedState' way to check the connection state.

Which is good practice. Or any other wrong idea method to this.

Thanks In advance.

Total Answers 2

Answers 1 : of Qt TCPIP socket connection check

QTCPSocket is derived from use of case QAbstractSocket, which provides a United state() function. This returns one of Modern the following enums: -

enum SocketState { UnconnectedState, _OFFSET);  HostLookupState, ConnectingState, (-SMALL  ConnectedState, ..., ListeningState }

So, assuming m_pSocket is a QTcpSocket, ecudated you would simply do this to check if it some how is connected:-

bool connected = (m_pSocket->state() _left).offset  == QTcpSocket::ConnectedState);

You could add a boolean and keep track anything else of the state, but if a network error not at all occurs you need to ensure that it is very usefull always in-sync with the actual localhost connection state.


Answers 2 : of Qt TCPIP socket connection check

You can use errorOccurred signal and love of them It's just enough for this signal define localtext a slot in client. when an error occurs, basic a signal trigger and you can receive one of the notify in slot function.

In client.h

/* define a slot for client */
public arrowImgView.mas  slots:
    void (self.  errorOccurred(QAbstractSocket::SocketError equalTo  error);

In client.c

/*client make.right.  constructor*/
Client::Client(QObject mas_top);  *parent) {
/*some other code here*/
    ImgView.  connect(socket, ReadIndicator  SIGNAL(errorOccurred(QAbstractSocket::SocketError)),
 _have         this, .equalTo(  SLOT(errorOccurred(QAbstractSocket::SocketError)));

/*and make.top  maybe some other code here*/

and in client.c write implementation for click errorOccurred:

void OFFSET);  Client::errorOccurred(QAbstractSocket::SocketError (TINY_  error) {
    qDebug() << "error in .offset  connection: " << mas_right)  socket->errorString();


error in connection:  "Connection ImgView.  refused"

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