can't sending data outside qtcpsocket thread

[rifky]

Hi,
anyone can help me about qtcpsocket with qthread after this .

i want to send message over qtcpsocket, but i don't know why i got error in Application logs

error : QSocketNotifier: Socket notifiers cannot be enabled or disabled from another thread

here is the readyRead() function :

void UpdataServerThread::readyRead()
{
    qDebug()<<updata_socket;
    qDebug()<<"connected_client_socket => "<<connected_client_socket;
    qDebug()<<"connected_client_ip => "<<connected_client_ip;

    QByteArray Data = updata_socket->readLine();
    QJsonDocument document = QJsonDocument::fromJson(Data.data());
    QJsonObject object = document.object();

    //qDebug()<<"current thread :"<<QThread::currentThread()<<" DEVICE::"<<updata_socket->peerAddress()<<"in : "<<Data.data();

    //authorize device
    if(Data.contains("devNumber")){
        connected_client_ip.insert(updata_socket->peerAddress(),object.value("devNumber").toString());
        QString str = "{\"msg\":\"Device registered successfully.\",\"timestamp\":"+QString::number(QDateTime::currentSecsSinceEpoch())+"}";
        QByteArray registered_device = str.toUtf8();

        ((QTcpSocket*)connected_client_socket.value(updata_socket->peerAddress()))->write(registered_device);

    }
    qDebug()<<"connected_client_ip::"<<connected_client_ip;
}

I've read topic similar topic like this, I haven't got solution.

in this example of threadedfortuneserver , i saw write() in run() function is work as well as my code in run() function to ,

how do I use write() outside run() function ?

here is my code

[rifky]

@rifky said in QSocketNotifier: Socket notifiers cannot be enabled or disabled from another thread:

solve with

connect(updata_socket,SIGNAL(readyRead()),this,SLOT(readyRead()),Qt::DirectConnection);

error : QSocketNotifier: Socket notifiers cannot be enabled or disabled from another thread

here is the readyRead() function :

void UpdataServerThread::readyRead()
{
    qDebug()<<updata_socket;
    qDebug()<<"connected_client_socket => "<<connected_client_socket;
    qDebug()<<"connected_client_ip => "<<connected_client_ip;

    QByteArray Data = updata_socket->readLine();
    QJsonDocument document = QJsonDocument::fromJson(Data.data());
    QJsonObject object = document.object();

    //qDebug()<<"current thread :"<<QThread::currentThread()<<" DEVICE::"<<updata_socket->peerAddress()<<"in : "<<Data.data();

    //authorize device
    if(Data.contains("devNumber")){
        connected_client_ip.insert(updata_socket->peerAddress(),object.value("devNumber").toString());
        QString str = "{\"msg\":\"Device registered successfully.\",\"timestamp\":"+QString::number(QDateTime::currentSecsSinceEpoch())+"}";
        QByteArray registered_device = str.toUtf8();

        ((QTcpSocket*)connected_client_socket.value(updata_socket->peerAddress()))->write(registered_device);

    }
    qDebug()<<"connected_client_ip::"<<connected_client_ip;
}

but i want to write outside ,

void UpdataServerThread::sendCommand(QByteArray cmd)
{
    qDebug()<<"current thread :@sendCommand"<<QThread::currentThread();

    //    qDebug()<<"connected_client_ip::"<<connected_client_ip;
    qDebug()<<"UpdataServerThread::sendCommand::"<<cmd;
    updata_socket->write("hi22");
}

how can i fix this code?

[KroMignon]

@rifky said in can't sending data outside qtcpsocket thread:

how can i fix this code?

Perhaps you could use QTimer::singleShot():

void UpdataServerThread::sendCommand(QByteArray cmd)
{
    qDebug()<<"current thread :@sendCommand"<<QThread::currentThread();

    //    qDebug()<<"connected_client_ip::"<<connected_client_ip;
    qDebug()<<"UpdataServerThread::sendCommand::"<<cmd;
    if(QThread::currentThread() != updata_socket->thread())
       QTimer::singleShot(0, updata_socket, [updata_socket](){
               updata_socket->write("hi22");
           });
    else
        updata_socket->write("hi22");
}

[rifky]

@KroMignon said in can't sending data outside qtcpsocket thread:

Perhaps you could use QTimer::singleShot():

void UpdataServerThread::sendCommand(QByteArray cmd)
{
    qDebug()<<"current thread :@sendCommand"<<QThread::currentThread();

    //    qDebug()<<"connected_client_ip::"<<connected_client_ip;
    qDebug()<<"UpdataServerThread::sendCommand::"<<cmd;
    if(QThread::currentThread() != updata_socket->thread())
       QTimer::singleShot(0, updata_socket, [updata_socket](){
               updata_socket->write("hi22");
           });
    else
        updata_socket->write("hi22");
}

thx for response but i got error :

updataserverthread.cpp:79:50: error: 'updata_socket' in capture list does not name a variable
updataserverthread.cpp:79:66: error: expected body of lambda expression

../qtcpsocket_w_qthread/updataserverthread.cpp:79:50: error: 'updata_socket' in capture list does not name a variable
            QTimer::singleShot(0, updata_socket,[updata_socket]()){
                                                 ^
../qtcpsocket_w_qthread/updataserverthread.cpp:79:66: error: expected body of lambda expression
            QTimer::singleShot(0, updata_socket,[updata_socket]()){
                                                                 ^
2 errors generated.

[KroMignon]

@rifky said in can't sending data outside qtcpsocket thread:

QTimer::singleShot(0, updata_socket,[updata_socket]()){

You have one extra closing parenthesis!
==> should be QTimer::singleShot(0, updata_socket,[updata_socket]() {

[rifky]

@KroMignon said in can't sending data outside qtcpsocket thread:

QTimer::singleShot(0, updata_socket,updata_socket {

    qDebug()<<"UpdataServerThread::sendCommand::"<<cmd;
    if(QThread::currentThread() != updata_socket->thread()){
        QTimer::singleShot(0, updata_socket,[updata_socket]() {
            updata_socket->write("hi22");
        });
    }else{
        updata_socket->write("hi22");
    }

is it correct ?

i still got error
updataserverthread.cpp:79:46: error: 'updata_socket' in capture list does not name a variable

[KroMignon]

@rifky said in can't sending data outside qtcpsocket thread:

is it correct ?

Why this question? Does it work or not?
If you are not confident with lambda functions take a look at this ==> https://medium.com/genymobile/how-c-lambda-expressions-can-improve-your-qt-code-8cd524f4ed9f

[rifky]

thx for help sir @KroMignon
i change to

 QTimer::singleShot(0, updata_socket,[this]() {

it's working

[KroMignon]

@rifky said in can't sending data outside qtcpsocket thread:

i change to
QTimer::singleShot(0, updata_socket,this {

it's working

Sorry my fault, I did not notice that updata_socket is not a local variable but a member of your class.
But this will not resolve your threading issue, I think you should change this to:

void UpdataServerThread::sendCommand(QByteArray cmd)
{
    qDebug()<<"current thread :@sendCommand"<<QThread::currentThread();

    //    qDebug()<<"connected_client_ip::"<<connected_client_ip;
    qDebug()<<"UpdataServerThread::sendCommand::"<<cmd;
    if(QThread::currentThread() != updata_socket->thread())
    {
       auto localVariable = updata_socket
       QTimer::singleShot(0, localVariable, [localVariable](){
               localVariable->write("hi22");
           });
    }
    else
        updata_socket->write("hi22");
}

[rifky]

@KroMignon no problem, thx for helping me, I really appreciate it