QTcpSocket Returning Error -1

plafratt

I am trying to create a very simple TCP connection using QTcpSocket and QTcpServer. The server appears to be receiving the connection fine. The client, though, is returning error -1. Does anyone know what might be causing this? The source code for the client is below.

I am able to write a working TCP client-server program program in Python that connects over port 10000. It works on the same machine on which this Qt program is failing.

I can provide the server code if needed. But, like I said, the server appears to be working. It just listens for a connection, and when the newConnection signal comes in, it sends some data. The client fails whether or not I send any data.

Any help is appreciated.

@int main( int argc, char * argv[] ) {
handler h;

  QTcpSocket *tcpSocket = new QTcpSocket;
  QObject::connect(tcpSocket,SIGNAL(readyRead()),
              &h,SLOT(commandRead()));

  tcpSocket->connectToHost("localhost",10000);

  tcpSocket->waitForConnected(5000);

  // returns -1
  cout<<tcpSocket->error()<<"\n";
  return 0;

}
@

Bruno13

Didn't you forget to instantiate a QCoreApplication object?

I'll start main function with:
@QCoreApplication app(argc, argv);@

plafratt

Bruno13:

Thank you for the reply. You are right, I had forgotten to do that. I hadn't given much attention to setting up and running the main loop, because I thought that I needed to deal with the error code that was being returned by the socket.

But it appears that if I go ahead and run app.exec() and ignore the error code, it can receive data just fine. I should've just ignored the error code, I guess. According to the QT documentation, though, this code means that "An unidentified error occurred."

Thank you again.