QTcpSocket - How do I know when it is disconnected ?

I have a thread that handles different connections from different computers.

I want to know when one of those connections (telnet) has been closed. I am trying to use the disconnect signal, but the method clientDisconnected is never called.

Code:

---

# include <QTcpSocket>
 
# include <iostream>
# include "client.h"
# include "server.h"
using namespace std;
 
Client :: Client(int socketDescriptor, Server *server, QObject *parent) : QThread(parent)
{
     this->socketDescriptor = socketDescriptor;
     this->server = server;
     chattingWith = new QString();
     connect(this, SIGNAL(finished()), this, SLOT(finished()));
}
 
 
void Client :: run()
{
     cout << "void Client :: run()\n";
     tcpSocket = new QTcpSocket();    
     if(!tcpSocket->setSocketDescriptor(socketDescriptor))
     {
          cout << "Error - tcpSocket descriptor\n";
          return;
     }
     connect(tcpSocket, SIGNAL(readyRead()), this, SLOT(readData()));
     connect(tcpSocket, SIGNAL(disconnected()), this, SLOT(clientDisconnected()));
     exec();
}
 
 
void Client :: readData()
{
     cout << "void Client :: readData()\n";
     server->addClient("12345", this);
}
 
 
void Client :: clientDisconnected()
{
     cout << "void Client :: clientDisconnected()\n";
}
 
void Client :: finished()
{
     cout << "The thread has finished\n";
}

---

Why ? What is wrong ?

Why is the QTcpSocket disconnect signal never emitted ?

I found the problem:

The signal was never emitted because I was only compiling the program with "make". In order to have the signal working I had to type "qmake" first, then "make".

Out of this test I assume that whenever I code something with SIGNALS and SLOTS, then I will "qmake" my program first.