non blocking QTcpSocket

[SIFE]

I made simple chat based in client-server model, I am able to send messages from client to server but not in reverse. I tried to implement my chat in non blocking mode, but it seems not work for me.
chat-0.4.tar.bz2

[Santosh Reddy]

Here are the problems int you code

Client

GuiClient::GuiClient(QWidget *parent) : QMainWindow(parent)
    , ui(new Ui::GuiClient()) //Add this
{
 
    ui->setupUi(this);
}

GuiClient::GuiClient(QWidget *parent) : QMainWindow(parent)
    , ui(new Ui::GuiClient()) //Add this
{

    ui->setupUi(this);
}

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Server

class GuiServer : public QMainWindow
{
...
private:
...
    QTcpSocket *client; //Add this
};
 
GuiServer::GuiServer(QWidget *parent) : QMainWindow(parent)
    , ui(new Ui::GuiServer())
    , client(0)
{
 
    ui->setupUi(this);
}
 
void GuiServer::readMsg()
 {
//    TcpSocket* client = (QTcpSocket*)sender(); //This will not work, and don't use this in your code, until you completely understand how signals, slots work.
 
    if(client) //user stored member variable, should be 0 if no client is connected
    {
        ... //Add all existing code here
    }
 }
 
void GuiServer::incomingConnection()
{
    if(client) //user stored member variable, should be 0 if no client is connected
        delete client;
    client = server->nextPendingConnection();
...
}
 
void GuiServer::sendMsg()
{
//    TcpSocket*  client = (QTcpSocket*)sender(); //This will not work, and don't use this in your code, until you completely understand how signals, slots work.
 
    if(client) //user stored member variable, should be 0 if no client is connected
    {
       ... //Add all existing code here
    }
}
 
void GuiServer::disconnected()
 {
    client = 0; //no client present
    qDebug("A client disconnected");
 }

class GuiServer : public QMainWindow
{
...
private:
...
    QTcpSocket *client; //Add this
};

GuiServer::GuiServer(QWidget *parent) : QMainWindow(parent)
    , ui(new Ui::GuiServer())
    , client(0)
{

    ui->setupUi(this);
}

void GuiServer::readMsg()
 {
//    TcpSocket* client = (QTcpSocket*)sender(); //This will not work, and don't use this in your code, until you completely understand how signals, slots work.

    if(client) //user stored member variable, should be 0 if no client is connected
    {
        ... //Add all existing code here
    }
 }

void GuiServer::incomingConnection()
{
    if(client) //user stored member variable, should be 0 if no client is connected
        delete client;
    client = server->nextPendingConnection();
...
}

void GuiServer::sendMsg()
{
//    TcpSocket*  client = (QTcpSocket*)sender(); //This will not work, and don't use this in your code, until you completely understand how signals, slots work.

    if(client) //user stored member variable, should be 0 if no client is connected
    {
       ... //Add all existing code here
    }
}

void GuiServer::disconnected()
 {
    client = 0; //no client present
    qDebug("A client disconnected");
 }

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Also this kind of server will be able to talk to only one client at a time. Multiple client handling is not implement, if tired to connect, server may crash

[SIFE]

Just two newbie question's:

GuiServer::GuiServer(QWidget *parent) : QMainWindow(parent)
, ui(new Ui::GuiServer())
, client(0)

GuiServer::GuiServer(QWidget *parent) : QMainWindow(parent)
, ui(new Ui::GuiServer())
, client(0)

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Are you here just instancing client object or it is some thing else.

TcpSocket* client = (QTcpSocket*)sender();

TcpSocket* client = (QTcpSocket*)sender();

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What is this exactly mean, because I just copy it from other source code and no look after search to found what is mean.