Cannot write with QTcpSocket

noele1995

The problem is in the send data function, when i do isWritable it retuns false, when i call write(d2) it returns -1, and when i try to flush it crashes with segmentation fault. Also i get this console output. Can it be for using more than 1 thread? how should i fix it? thanks
@QSocketNotifier: socket notifiers cannot be disabled from another thread
QSocketNotifier: Multiple socket notifiers for same socket 560 and type Read
(Internal error: pc 0x0 in read in psymtab, but not in symtab.)
QIODevice::write: ReadOnly device@

@
//in the header...
typedef struct {QString name;QString pcName;QString userName;QString admin;QString flagCode;QString IP;QTcpSocket *sck;}client;
QList<client *> Clients;

fMain::fMain(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::fMain)
{
ui->setupUi(this);

for(int i = 0;i < 3;i++)
{
    newConexPorts[i] = 1181 + i;
    newConexServers[i] = new QTcpServer(this);
}

    //SOCKETS
connect(this,SIGNAL(signalRefreshConexList()),this,SLOT(slotRefreshConexList()));
for(int i = 0;i < 3;i++)
{
    connect(newConexServers[i],SIGNAL(newConnection()),this,SLOT(incomingConnection()));
}

}

void fMain::socket_Send(client *Client,const QString &d)
{
QByteArray d2;
d2.append(d);
bool _a = Client->sck->isWritable();
qint64 bytes = Client->sck->write(d2);
Client->sck->flush();
Client->sck->waitForBytesWritten();
}

void fMain::incomingConnection(void)
{
QTcpServer *SERVER = (QTcpServer *)QObject::sender();

if(SERVER->hasPendingConnections())
{
    QTcpSocket *SOCKET = SERVER->nextPendingConnection();

    //thread
    newConexThread *thread = new newConexThread;
    thread->setThreadData(SOCKET,this);
    connect(thread,SIGNAL(signalRefreshConexList()),this,SLOT(slotRefreshConexList()));
    connect(thread,SIGNAL(signalSocketNotLogged(QTcpSocket*)),this,SLOT(slotDeleteSocket(QTcpSocket*)));
    thread->start();
}

}

void fMain::slotDeleteSocket(QTcpSocket *s)
{
s->close();
s->deleteLater();
}

void fMain::slotDeleteSocket2(void)
{
QTcpSocket *SOCKET = (QTcpSocket *)QObject::sender();

if(!Clients.empty())
{
    foreach (client *Client, Clients)
    {
        if(Client->sck == SOCKET)
        {
            Clients.removeOne(Client);
        }
    }
}

SOCKET->close();
SOCKET->deleteLater();

emit signalRefreshConexList();

}

void fMain::slotSocketReadyRead(void)
{
QTcpSocket *SOCKET = (QTcpSocket *)QObject::sender();
QString dataReceived = QString(SOCKET->readAll());
QStringList listData = dataReceived.split("|");
client *client_sender;

//code...
}

//NEW_CONEX_THREAD

void newConexThread::setThreadData(QTcpSocket *s,fMain *f)
{
SOCKET = s;
frm = f;
}

void newConexThread::run()
{
if(SOCKET->state() != 3)
{
SOCKET->waitForConnected();
}
if(SOCKET->state() == 3)
{
if(SOCKET->waitForReadyRead())
{
QString dataReceived = QString(SOCKET->readAll());
QStringList listData = dataReceived.split("|");

        if(listData.at(0) == NEW_CONEX_ID)
        {
            if (!(listData.length() < 7))
            {
                if (listData.at(6) == frm->password)
                {
                    connect(SOCKET,SIGNAL(disconnected()),frm,SLOT(slotDeleteSocket2()));

                    client *Client = new client;

                    Client->name = listData.at(1);

                    Client->IP = SOCKET->peerAddress().toString();

                    Client->sck = SOCKET;

                    frm->Clients.append(Client);

                    connect(SOCKET,SIGNAL(disconnected()),frm,SLOT(slotDeleteSocket2()));
                    connect(SOCKET,SIGNAL(readyRead()),frm,SLOT(slotSocketReadyRead()));

                    emit signalRefreshConexList();
                    this->deleteLater();
                    return;
                }
            }
        }
    }
}
emit signalSocketNotLogged(SOCKET);
this->deleteLater();
return;

}@

mcosta

Hi,

when is socket_Send() called?

I think you have a syncronization problem.

noele1995

It is called on a slot of a button but the socket isnt reading or doing anything else, just waiting.

mcosta

Hi,

what I see is that you set Client->sck only after receiving something; are you sure your socket field are set when you call send?

noele1995

Thats ok its for loggin the socket, i solved the problem, it was an error on calling the function, the pointer that i was passing was null. Sorry and thanks for yout time

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Cannot write with QTcpSocket