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

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

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  • C CP71
    1 Apr 2019, 11:30

    @Dooham

    Check where you create objects in your thread, beware they are created in run slot.

    See
    https://mayaposch.wordpress.com/2011/11/01/how-to-really-truly-use-qthreads-the-full-explanation/

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    Dooham
    wrote on 1 Apr 2019, 11:39 last edited by
    #4

    @CP71 Thaks for your answer. I thing that all the QObects that I created are in the run slot. I just created the QTCPSocket and it is in the reun slot in the third line. When I read this article, I tried to use the movetoThread(this) but I didnt work.

    C 1 Reply Last reply 1 Apr 2019, 17:10
    1
    • D Dooham
      1 Apr 2019, 11:39

      @CP71 Thaks for your answer. I thing that all the QObects that I created are in the run slot. I just created the QTCPSocket and it is in the reun slot in the third line. When I read this article, I tried to use the movetoThread(this) but I didnt work.

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      CP71
      wrote on 1 Apr 2019, 17:10 last edited by
      #5

      @Dooham
      You are welcome!
      Where do you declare and use QNativeSocketEngine object?
      I think I don’t see it in your code?

      D 1 Reply Last reply 1 Apr 2019, 17:26
      1
      • C CP71
        1 Apr 2019, 17:10

        @Dooham
        You are welcome!
        Where do you declare and use QNativeSocketEngine object?
        I think I don’t see it in your code?

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        Dooham
        wrote on 1 Apr 2019, 17:26 last edited by
        #6

        @CP71 To be honest, I dont know where is declare. First of all I dont know what is exactly it. I got an example of multithreatings server and adapte it to my trouble. Now, I am trying to change the QTcpSocket from a declare variable to a local variable (I have read that this could solve the problem), but I not sure about how to adapt the function getMsg to read my socket.

        C 1 Reply Last reply 1 Apr 2019, 17:30
        1
        • D Dooham
          1 Apr 2019, 17:26

          @CP71 To be honest, I dont know where is declare. First of all I dont know what is exactly it. I got an example of multithreatings server and adapte it to my trouble. Now, I am trying to change the QTcpSocket from a declare variable to a local variable (I have read that this could solve the problem), but I not sure about how to adapt the function getMsg to read my socket.

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          CP71
          wrote on 1 Apr 2019, 17:30 last edited by CP71 4 Jan 2019, 17:33
          #7

          @Dooham
          sorry!
          I believe is a my stupid question :(
          i think it is created when you create a socket

          https://code.woboq.org/kde/qt4/src/network/socket/qnativesocketengine.cpp.html#_ZN19QNativeSocketEngineD1Ev

          D 1 Reply Last reply 1 Apr 2019, 17:36
          1
          • C CP71
            1 Apr 2019, 17:30

            @Dooham
            sorry!
            I believe is a my stupid question :(
            i think it is created when you create a socket

            https://code.woboq.org/kde/qt4/src/network/socket/qnativesocketengine.cpp.html#_ZN19QNativeSocketEngineD1Ev

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            Dooham
            wrote on 1 Apr 2019, 17:36 last edited by
            #8

            @CP71 Yeah, seeing that socumntation, I think you are right, but I dont understand why appears that error. I wrote the same code that the example that I saw, and that worked , but when I adapted to my case it failed.

            C 1 Reply Last reply 1 Apr 2019, 18:53
            1
            • D Dooham
              1 Apr 2019, 17:36

              @CP71 Yeah, seeing that socumntation, I think you are right, but I dont understand why appears that error. I wrote the same code that the example that I saw, and that worked , but when I adapted to my case it failed.

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              CP71
              wrote on 1 Apr 2019, 18:53 last edited by
              #9

              @Dooham
              I have a dubt.
              Maybe I’m beeing wrong but I think that your server musn't create TcpSocket but it should waiting a new connection:

              In your server
              QObject::connect( this, SIGNAL(newConnection()), this, SLOT(newConnection()) );

              In newConnection:

              //////////////////////////////////////////////////////////////////////////////////////
              ///
              void MyServer::newConnection()
              {
              QTcpSocket *socket = server->nextPendingConnection();
              if ( socket )
              {
              … doing your procedure
              }
              }

              I don’t see where incomingConnection is called.

              But maybe it is already so.

              D 1 Reply Last reply 1 Apr 2019, 19:09
              1
              • C CP71
                1 Apr 2019, 18:53

                @Dooham
                I have a dubt.
                Maybe I’m beeing wrong but I think that your server musn't create TcpSocket but it should waiting a new connection:

                In your server
                QObject::connect( this, SIGNAL(newConnection()), this, SLOT(newConnection()) );

                In newConnection:

                //////////////////////////////////////////////////////////////////////////////////////
                ///
                void MyServer::newConnection()
                {
                QTcpSocket *socket = server->nextPendingConnection();
                if ( socket )
                {
                … doing your procedure
                }
                }

                I don’t see where incomingConnection is called.

                But maybe it is already so.

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                Dooham
                wrote on 1 Apr 2019, 19:09 last edited by
                #10

                @CP71 I think that is not neccesary,because of the function incomingConnection. When I see this Code I had a similar doubt, but this function is a virtual function of QtcpServer that is called when a newConnection Signal appears. In this code,I just edit the function a bit.
                Maybe the trouble would be that I didnt called the write function from the run, and this could be problematic. In a while, I will try to rewrite the code un order to call the function that write the message from the run

                D C 2 Replies Last reply 2 Apr 2019, 07:32
                1
                • S Offline
                  S Offline
                  SGaist
                  Lifetime Qt Champion
                  wrote on 1 Apr 2019, 20:11 last edited by
                  #11

                  Hi,

                  Are you trying to implement a threaded server ? If so, you can take a look at the threaded fortune server example.

                  Interested in AI ? www.idiap.ch
                  Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

                  D 1 Reply Last reply 1 Apr 2019, 20:39
                  2
                  • S SGaist
                    1 Apr 2019, 20:11

                    Hi,

                    Are you trying to implement a threaded server ? If so, you can take a look at the threaded fortune server example.

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                    Dooham
                    wrote on 1 Apr 2019, 20:39 last edited by
                    #12

                    @SGaist Thanks you, I think this example support my idea, that the trouble is that I dont call the function that write the message from the run function but from a external slot that, in theory dont interact with this routine. Am I right?
                    On the other hand, do you know any method to initialize the serial port from the thread just one time (at the begginning of the program)? I have been thinking during the last hour but I dont archive any progress
                    Thanks again

                    1 Reply Last reply
                    0
                    • S Offline
                      S Offline
                      SGaist
                      Lifetime Qt Champion
                      wrote on 1 Apr 2019, 20:42 last edited by
                      #13

                      What is your exact use of QSerialPort ?

                      Interested in AI ? www.idiap.ch
                      Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

                      D 1 Reply Last reply 1 Apr 2019, 21:10
                      1
                      • S SGaist
                        1 Apr 2019, 20:42

                        What is your exact use of QSerialPort ?

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                        Dooham
                        wrote on 1 Apr 2019, 21:10 last edited by
                        #14

                        @SGaist I read the continuous message that a device (a Pixhawk). Every thing that I receive a package of message ( the serial port send me package of message) in form of QByteArray I send it to a client that can decode them

                        1 Reply Last reply
                        0
                        • D Dooham
                          1 Apr 2019, 19:09

                          @CP71 I think that is not neccesary,because of the function incomingConnection. When I see this Code I had a similar doubt, but this function is a virtual function of QtcpServer that is called when a newConnection Signal appears. In this code,I just edit the function a bit.
                          Maybe the trouble would be that I didnt called the write function from the run, and this could be problematic. In a while, I will try to rewrite the code un order to call the function that write the message from the run

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                          Dooham
                          wrote on 2 Apr 2019, 07:32 last edited by
                          #15

                          @Dooham That didn't work, I dont know what is the trouble, I have seen that there are two different QThread ID, and that is probably the cause of the issue:
                          0_1554190211682_3c2ed1b3-b00e-4493-9839-8182529d1966-image.png
                          As you can see, I got the adress of the Thread that I generate with the incomingConnection but, in some point I create an Object that its parent is other QThread.
                          I dont know what to do.

                          1 Reply Last reply
                          0
                          • D Dooham
                            1 Apr 2019, 19:09

                            @CP71 I think that is not neccesary,because of the function incomingConnection. When I see this Code I had a similar doubt, but this function is a virtual function of QtcpServer that is called when a newConnection Signal appears. In this code,I just edit the function a bit.
                            Maybe the trouble would be that I didnt called the write function from the run, and this could be problematic. In a while, I will try to rewrite the code un order to call the function that write the message from the run

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                            C Offline
                            CP71
                            wrote on 2 Apr 2019, 08:34 last edited by CP71 4 Feb 2019, 08:36
                            #16

                            @Dooham
                            I think you don't call addPendingConnection or it seems so

                            0_1554194144567_013b5385-d81d-4dd1-be58-d950d072f8e1-image.png

                            1 Reply Last reply
                            0
                            • D Dooham
                              1 Apr 2019, 09:52

                              Hello,
                              I am having this trouble since two days ago and I am not sure how solve this error.
                              I made a code for a server that can handle multiple connections, my goal is to read in the server messages from a device in the serialPort, send this messages to all the clients connected to my server and, from the clients can send message to the device. To do this, I saw that I need programming a Thread that can handle the multiple connections.
                              I made this code:

                              myserver.cpp

                              #include "myserver.h"
                              
                              MyServer::MyServer(QObject *parent) : QTcpServer (parent)
                              {
                              
                              }
                              
                              void MyServer::startServer()
                              {
                                  if(!this->listen(QHostAddress::Any, 9999)){
                              qDebug()<<"Server not started";
                                  }else {
                              qDebug()<<"Server listening";
                                  }
                              }
                              
                              void MyServer::startSerialPort()
                              {
                                 mipuerto2 = new MySerialPort;
                                 connect(mipuerto2, SIGNAL(msgChanged()), this, SLOT(getMens()));
                                 mipuerto2->openSerialPort();
                              }
                              
                              void MyServer::getMens()
                              {
                                  arr2=mipuerto2->getMensaje();
                              
                                  emit mensChanged(&arr2);
                              }
                              
                              void MyServer::sendMens(QByteArray *arraySend)
                              {
                              mipuerto2->writeMsg(*arraySend);
                              }
                              
                              
                              void MyServer::incomingConnection(int socketDescriptor)
                              {
                              
                              qDebug()<<socketDescriptor<<"Connecting... ";
                              MyThread *thread=new MyThread(socketDescriptor, this);
                              connect(thread, SIGNAL(finished()), thread, SLOT(deleteLater()));
                              connect(this, SIGNAL(mensChanged(QByteArray * )), thread, SLOT(getMsg(QByteArray *)));
                              connect(thread, SIGNAL(mensajeEnviar(QByteArray * )), this,SLOT(sendMens(QByteArray * )));
                              thread->start();
                              
                              }
                              

                              mythread.cpp

                              #include "mythread.h"
                              
                              MyThread::MyThread(int ID, QObject *parent) : QThread(parent)
                              {
                                  this->socketDescriptor=ID;
                              
                              }
                              
                              void MyThread::run()
                              {
                              //thread start here
                                  qDebug()<<socketDescriptor<< " Starting thread";
                                  socket = new QTcpSocket();
                                  if(!socket->setSocketDescriptor(this->socketDescriptor)){
                                      emit error(socket->error());
                              
                                  }
                              
                                  connect(socket, SIGNAL(readyRead()), this, SLOT(readyRead()), Qt::DirectConnection);
                                  connect(socket, SIGNAL(disconnected()), this, SLOT(disconnected()), Qt::DirectConnection);
                              
                                  qDebug() << socketDescriptor<< " Client Connect";
                              
                              
                              
                                  exec();
                              }
                              
                              void MyThread::readyRead()
                              {
                              
                                  msgSend="";
                                 // socket->waitForReadyRead(100);
                                  msgSend=socket->readAll();
                              
                                      qDebug()<<msgSend.toHex();
                              emit mensajeEnviar(&msgSend);
                              }
                              
                              void MyThread::disconnected()
                              {
                                  qDebug() << socketDescriptor<< " Disconnected";
                              
                                  socket->deleteLater();
                              
                                  exit(0);
                              }
                              
                              void MyThread::getMsg(QByteArray * array)
                              {
                              
                                  socket->write(*array);
                                  socket->waitForBytesWritten(3000);
                              
                              }
                              

                              So everytime that, the serial port read a new group of messages, emit a signal to send them.
                              With this code, I can read the messages from the client and send message (I haven't probe with more connections yet), but when I read I get this error in the server console:

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

                              This error appears every time that a new messages arrives to the server from the serial port. Does anyone know what I can do to solve it?
                              Thanks.

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                              Dooham
                              wrote on 2 Apr 2019, 08:40 last edited by
                              #17

                              @Dooham @CP71 @SGaist Finally I could "solve" the trouble that I had. I had to create other class that has the QTcpSocket, and create that class inside the run function of the thread as a local variable. However I found some trouble with the write method, I dont know how to solve it. The trouble is that dont read the client (with the previous code I could read, the messaged from the client). This is my code:

                              myserver.cpp

                              MyServer::MyServer(QObject *parent) : QTcpServer (parent)
                              {
                              
                              }
                              
                              void MyServer::startServer()
                              {
                                  if(!this->listen(QHostAddress::Any, 9999)){
                              qDebug()<<"Server not started";
                                  }else {
                              qDebug()<<"Server listening";
                                  }
                              }
                              
                              void MyServer::startSerialPort()
                              {
                                 mipuerto2 = new MySerialPort;
                                connect(mipuerto2, SIGNAL(msgChanged(QByteArray*)), this, SLOT(getMens(QByteArray*)));
                                 mipuerto2->openSerialPort();
                              }
                              
                              void MyServer::getMens(QByteArray*array)
                              {
                              
                              
                              
                                  emit mensChanged(array);
                              }
                              
                              void MyServer::sendMens(QByteArray *arraySend)
                              {
                              mipuerto2->writeMsg(*arraySend);
                              }
                              
                              
                              void MyServer::incomingConnection(int socketDescriptor)
                              {
                              
                              qDebug()<<socketDescriptor<<"Connecting... ";
                              MyThread *thread=new MyThread(socketDescriptor, this);
                              
                              qDebug()<<thread;
                              connect(thread, SIGNAL(finished()), thread, SLOT(deleteLater()));
                              connect(this, SIGNAL(mensChanged(QByteArray * )), thread, SLOT(getMsg(QByteArray *)));
                              connect(thread, SIGNAL(mensajeEnviar(QByteArray * )), this,SLOT(sendMens(QByteArray * )));
                              
                              
                              
                              thread->start();
                              
                              }
                              
                              

                              myserialport.cpp

                              #include "myserialport.h"
                              #include <QObject>
                              #include <QtSerialPort/QSerialPort>
                              #include <QDebug>
                              
                              
                              MySerialPort::MySerialPort()
                              {
                                  serial = new QSerialPort(this);
                                  data= "";
                              
                                  connect(serial, SIGNAL(readyRead()), this, SLOT(readData()));
                                  openSerialPort();
                              
                              }
                              
                              void MySerialPort::openSerialPort()
                              {
                                  serial->setPortName("COM4");
                                  //serial->setBaudRate(QSerialPort::Baud9600);
                                  serial->setBaudRate(QSerialPort::Baud115200);
                                  serial->setDataBits(QSerialPort::Data8);
                                  serial->setParity(QSerialPort::NoParity);
                                  serial->setStopBits(QSerialPort::OneStop);
                                  serial->setFlowControl(QSerialPort::NoFlowControl);
                                  serial->open(QIODevice::ReadWrite);
                              
                              
                              }
                              
                              void MySerialPort::closeSerialPort()
                              {
                                  if(serial->isOpen()){
                                      serial->close();
                                  }
                              }
                              
                              void MySerialPort::readData()
                              {
                              
                                 data = serial->readAll();
                                  dataAux=data.toHex();
                                  emit msgChanged(&data);
                              
                              }
                              
                              QByteArray MySerialPort::getMensaje()
                              {
                                  return data;
                              }
                              
                              void MySerialPort::writeMsg(QByteArray datos)
                              {
                              
                                  serial->write(datos);
                              
                              }
                              
                              

                              mythread.cpp

                              #include "mythread.h"
                              #include "mysocket.h"
                              MyThread::MyThread(int ID, QObject *parent) : QThread(parent)
                              {
                                  this->socketDescriptor=ID;
                              
                              
                              }
                              
                              void MyThread::run()
                              {
                                  qDebug()<<socketDescriptor<< " Starting thread";
                                  MySocket socket2(this->socketDescriptor);
                                  //Revisar mas tarde
                                  /*if(!socket2.setSocketDescriptor(this->socketDescriptor)){
                                      emit error(socket->error());
                              
                                  }*/
                              
                                  /*connect(socket2, SIGNAL(readyRead()), this, SLOT(readyRead()), Qt::DirectConnection);*/
                              
                              
                                  connect(this, SIGNAL(mensajeRecibido(QByteArray*)), &socket2, SLOT(getMsg(QByteArray*)));
                                  connect(&socket2, SIGNAL(disconnected()), this, SLOT(disconnected()));
                                  connect(&socket2, SIGNAL(mensajeEnviarSocket(QByteArray*)), this, SLOT(readyRead(QByteArray*)));
                                  qDebug() << socketDescriptor<< " Client Connect";
                              
                              
                              
                                  exec();
                              }
                              
                              void MyThread::readyRead(QByteArray*arraySent)
                              {
                              
                              
                                  qDebug()<<arraySent->toHex();
                                  emit mensajeEnviar(arraySent);
                              }
                              
                              void MyThread::disconnected()
                              {
                                  qDebug() << socketDescriptor<< " Disconnected";
                              
                                  //socket->deleteLater();
                              
                                  exit(0);
                              }
                              
                              void MyThread::getMsg(QByteArray * array)
                              {
                                  emit mensajeRecibido(array);
                              
                              
                              }
                              

                              mysocket.cpp (This is the new class)

                              #include "mysocket.h"
                              
                              MySocket::MySocket(int socketDescriptor)
                              {
                              socket= new QTcpSocket;
                              socket->setSocketDescriptor(socketDescriptor);
                              connect(this, SIGNAL(disconnected()), this, SLOT(desconexion()));
                              connect(this, SIGNAL(readyRead()), this, SLOT(leerMsg()));
                              qDebug()<<"Hola";
                              }
                              
                              void MySocket::leerMsg()
                              {
                                  msgSend="";
                                  // socket->waitForReadyRead(100);
                                  msgSend=socket->readAll();
                              
                                  qDebug()<<msgSend.toHex();
                                  emit mensajeEnviarSocket(&msgSend);
                              }
                              
                              void MySocket::desconexion()
                              {
                                 socket->deleteLater();
                              }
                              
                              void MySocket::getMsg(QByteArray *array)
                              {
                              
                                  arr=*array;
                                  //qDebug()<<arr;
                                 // qDebug()<<"server a thread";
                                  socket->write(arr);
                                  socket->flush();
                                  socket->waitForBytesWritten(3000);
                              }
                              
                              

                              mysocket.h

                              #ifndef MYSOCKET_H
                              #define MYSOCKET_H
                              
                              #include <QObject>
                              #include <QTcpSocket>
                              
                              class MySocket:public QTcpSocket
                              {
                                  Q_OBJECT
                              public:
                                  MySocket(int socketDescriptor);
                              signals:
                                  void mensajeEnviarSocket(QByteArray *arraySend);
                              
                              public slots:
                                  void leerMsg();
                                  void desconexion();
                                  void getMsg(QByteArray *array);
                              private:
                                  QTcpSocket *socket;
                                  QByteArray arr;
                                  QByteArray msgSend;
                              };
                              
                              #endif // MYSOCKET_H
                              

                              With this code, I can read the serial port and sending to the client without troubles (I also tried with the telnet command and two connections, and this could with them). But I can read the messages sent. Another trouble that I saw, is that, when I disconect the client, in the server appears the following error: QAbstractSocket::waitForBytesWritten() is not allowed in UnconnectedState

                              Does anyone knows how I can solve this issues?
                              Thanks for your help.

                              D 1 Reply Last reply 2 Apr 2019, 09:01
                              0
                              • D Dooham
                                2 Apr 2019, 08:40

                                @Dooham @CP71 @SGaist Finally I could "solve" the trouble that I had. I had to create other class that has the QTcpSocket, and create that class inside the run function of the thread as a local variable. However I found some trouble with the write method, I dont know how to solve it. The trouble is that dont read the client (with the previous code I could read, the messaged from the client). This is my code:

                                myserver.cpp

                                MyServer::MyServer(QObject *parent) : QTcpServer (parent)
                                {
                                
                                }
                                
                                void MyServer::startServer()
                                {
                                    if(!this->listen(QHostAddress::Any, 9999)){
                                qDebug()<<"Server not started";
                                    }else {
                                qDebug()<<"Server listening";
                                    }
                                }
                                
                                void MyServer::startSerialPort()
                                {
                                   mipuerto2 = new MySerialPort;
                                  connect(mipuerto2, SIGNAL(msgChanged(QByteArray*)), this, SLOT(getMens(QByteArray*)));
                                   mipuerto2->openSerialPort();
                                }
                                
                                void MyServer::getMens(QByteArray*array)
                                {
                                
                                
                                
                                    emit mensChanged(array);
                                }
                                
                                void MyServer::sendMens(QByteArray *arraySend)
                                {
                                mipuerto2->writeMsg(*arraySend);
                                }
                                
                                
                                void MyServer::incomingConnection(int socketDescriptor)
                                {
                                
                                qDebug()<<socketDescriptor<<"Connecting... ";
                                MyThread *thread=new MyThread(socketDescriptor, this);
                                
                                qDebug()<<thread;
                                connect(thread, SIGNAL(finished()), thread, SLOT(deleteLater()));
                                connect(this, SIGNAL(mensChanged(QByteArray * )), thread, SLOT(getMsg(QByteArray *)));
                                connect(thread, SIGNAL(mensajeEnviar(QByteArray * )), this,SLOT(sendMens(QByteArray * )));
                                
                                
                                
                                thread->start();
                                
                                }
                                
                                

                                myserialport.cpp

                                #include "myserialport.h"
                                #include <QObject>
                                #include <QtSerialPort/QSerialPort>
                                #include <QDebug>
                                
                                
                                MySerialPort::MySerialPort()
                                {
                                    serial = new QSerialPort(this);
                                    data= "";
                                
                                    connect(serial, SIGNAL(readyRead()), this, SLOT(readData()));
                                    openSerialPort();
                                
                                }
                                
                                void MySerialPort::openSerialPort()
                                {
                                    serial->setPortName("COM4");
                                    //serial->setBaudRate(QSerialPort::Baud9600);
                                    serial->setBaudRate(QSerialPort::Baud115200);
                                    serial->setDataBits(QSerialPort::Data8);
                                    serial->setParity(QSerialPort::NoParity);
                                    serial->setStopBits(QSerialPort::OneStop);
                                    serial->setFlowControl(QSerialPort::NoFlowControl);
                                    serial->open(QIODevice::ReadWrite);
                                
                                
                                }
                                
                                void MySerialPort::closeSerialPort()
                                {
                                    if(serial->isOpen()){
                                        serial->close();
                                    }
                                }
                                
                                void MySerialPort::readData()
                                {
                                
                                   data = serial->readAll();
                                    dataAux=data.toHex();
                                    emit msgChanged(&data);
                                
                                }
                                
                                QByteArray MySerialPort::getMensaje()
                                {
                                    return data;
                                }
                                
                                void MySerialPort::writeMsg(QByteArray datos)
                                {
                                
                                    serial->write(datos);
                                
                                }
                                
                                

                                mythread.cpp

                                #include "mythread.h"
                                #include "mysocket.h"
                                MyThread::MyThread(int ID, QObject *parent) : QThread(parent)
                                {
                                    this->socketDescriptor=ID;
                                
                                
                                }
                                
                                void MyThread::run()
                                {
                                    qDebug()<<socketDescriptor<< " Starting thread";
                                    MySocket socket2(this->socketDescriptor);
                                    //Revisar mas tarde
                                    /*if(!socket2.setSocketDescriptor(this->socketDescriptor)){
                                        emit error(socket->error());
                                
                                    }*/
                                
                                    /*connect(socket2, SIGNAL(readyRead()), this, SLOT(readyRead()), Qt::DirectConnection);*/
                                
                                
                                    connect(this, SIGNAL(mensajeRecibido(QByteArray*)), &socket2, SLOT(getMsg(QByteArray*)));
                                    connect(&socket2, SIGNAL(disconnected()), this, SLOT(disconnected()));
                                    connect(&socket2, SIGNAL(mensajeEnviarSocket(QByteArray*)), this, SLOT(readyRead(QByteArray*)));
                                    qDebug() << socketDescriptor<< " Client Connect";
                                
                                
                                
                                    exec();
                                }
                                
                                void MyThread::readyRead(QByteArray*arraySent)
                                {
                                
                                
                                    qDebug()<<arraySent->toHex();
                                    emit mensajeEnviar(arraySent);
                                }
                                
                                void MyThread::disconnected()
                                {
                                    qDebug() << socketDescriptor<< " Disconnected";
                                
                                    //socket->deleteLater();
                                
                                    exit(0);
                                }
                                
                                void MyThread::getMsg(QByteArray * array)
                                {
                                    emit mensajeRecibido(array);
                                
                                
                                }
                                

                                mysocket.cpp (This is the new class)

                                #include "mysocket.h"
                                
                                MySocket::MySocket(int socketDescriptor)
                                {
                                socket= new QTcpSocket;
                                socket->setSocketDescriptor(socketDescriptor);
                                connect(this, SIGNAL(disconnected()), this, SLOT(desconexion()));
                                connect(this, SIGNAL(readyRead()), this, SLOT(leerMsg()));
                                qDebug()<<"Hola";
                                }
                                
                                void MySocket::leerMsg()
                                {
                                    msgSend="";
                                    // socket->waitForReadyRead(100);
                                    msgSend=socket->readAll();
                                
                                    qDebug()<<msgSend.toHex();
                                    emit mensajeEnviarSocket(&msgSend);
                                }
                                
                                void MySocket::desconexion()
                                {
                                   socket->deleteLater();
                                }
                                
                                void MySocket::getMsg(QByteArray *array)
                                {
                                
                                    arr=*array;
                                    //qDebug()<<arr;
                                   // qDebug()<<"server a thread";
                                    socket->write(arr);
                                    socket->flush();
                                    socket->waitForBytesWritten(3000);
                                }
                                
                                

                                mysocket.h

                                #ifndef MYSOCKET_H
                                #define MYSOCKET_H
                                
                                #include <QObject>
                                #include <QTcpSocket>
                                
                                class MySocket:public QTcpSocket
                                {
                                    Q_OBJECT
                                public:
                                    MySocket(int socketDescriptor);
                                signals:
                                    void mensajeEnviarSocket(QByteArray *arraySend);
                                
                                public slots:
                                    void leerMsg();
                                    void desconexion();
                                    void getMsg(QByteArray *array);
                                private:
                                    QTcpSocket *socket;
                                    QByteArray arr;
                                    QByteArray msgSend;
                                };
                                
                                #endif // MYSOCKET_H
                                

                                With this code, I can read the serial port and sending to the client without troubles (I also tried with the telnet command and two connections, and this could with them). But I can read the messages sent. Another trouble that I saw, is that, when I disconect the client, in the server appears the following error: QAbstractSocket::waitForBytesWritten() is not allowed in UnconnectedState

                                Does anyone knows how I can solve this issues?
                                Thanks for your help.

                                D Offline
                                D Offline
                                Dooham
                                wrote on 2 Apr 2019, 09:01 last edited by
                                #18

                                @Dooham I have solved the trouble with waitforBytesWritten with the function: waitforConnected() that return true if is connected so, I just read if the socket is connected. But I cant read yet.

                                C 2 Replies Last reply 2 Apr 2019, 12:41
                                1
                                • D Dooham
                                  2 Apr 2019, 09:01

                                  @Dooham I have solved the trouble with waitforBytesWritten with the function: waitforConnected() that return true if is connected so, I just read if the socket is connected. But I cant read yet.

                                  C Offline
                                  C Offline
                                  CP71
                                  wrote on 2 Apr 2019, 12:41 last edited by
                                  #19

                                  @Dooham
                                  Hi,
                                  I quickly watch your code.
                                  I see a thing that is a bit dangerous or I think so, you emit a pointer and not a copy of data without thread synchronization, don’t you?

                                  D 1 Reply Last reply 2 Apr 2019, 14:29
                                  1
                                  • D Dooham
                                    2 Apr 2019, 09:01

                                    @Dooham I have solved the trouble with waitforBytesWritten with the function: waitforConnected() that return true if is connected so, I just read if the socket is connected. But I cant read yet.

                                    C Offline
                                    C Offline
                                    CP71
                                    wrote on 2 Apr 2019, 13:03 last edited by
                                    #20

                                    @Dooham
                                    And more,
                                    I think you must call addPendingConnection in your incomingConnection

                                    void MyServer::incomingConnection(int socketDescriptor)
                                    {

                                    …

                                    addPendingConnection( thread→GetQTcpSocketPointer() )

                                    thread->start();

                                    }

                                    1 Reply Last reply
                                    1
                                    • C CP71
                                      2 Apr 2019, 12:41

                                      @Dooham
                                      Hi,
                                      I quickly watch your code.
                                      I see a thing that is a bit dangerous or I think so, you emit a pointer and not a copy of data without thread synchronization, don’t you?

                                      D Offline
                                      D Offline
                                      Dooham
                                      wrote on 2 Apr 2019, 14:29 last edited by
                                      #21

                                      @CP71 I dont know if this is dangerous or not, but it is easy to change, I think. So I will change it later to pass a QByteArray and not a QByteArray pointer. Related to pendingConnection, I don know if this is necessary or not. I am just going to have a few connection. I proved ths code with three clients and I didnt have troubles. With the exception that I cant send message to the serialport, but is a problem that dont depend of the number of connections. However I saw that the trouble is that the socket dont emit the signal readyRead in the socket of the server when I receive a message from a client.

                                      C 1 Reply Last reply 2 Apr 2019, 17:28
                                      1
                                      • D Dooham
                                        2 Apr 2019, 14:29

                                        @CP71 I dont know if this is dangerous or not, but it is easy to change, I think. So I will change it later to pass a QByteArray and not a QByteArray pointer. Related to pendingConnection, I don know if this is necessary or not. I am just going to have a few connection. I proved ths code with three clients and I didnt have troubles. With the exception that I cant send message to the serialport, but is a problem that dont depend of the number of connections. However I saw that the trouble is that the socket dont emit the signal readyRead in the socket of the server when I receive a message from a client.

                                        C Offline
                                        C Offline
                                        CP71
                                        wrote on 2 Apr 2019, 17:28 last edited by
                                        #22

                                        @Dooham
                                        Ok,
                                        When we have some problems we say, “the computer has always reason”, well almost always.
                                        I’m joking ;)

                                        I already done a TCP Server but I took another road and I hadn't got special problems, so now I haven’t ideas. :(

                                        If I can, I suggest you to solve one problem at a time, I would start at the end, as per QtcpSocket, to try to understand why readyRead seems not working I should check the following checks:

                                        • Check with Wireshark or other tools if TCP packets arrive to your device
                                        • Check by debug text info about QTcpSocket that you have created (e.g. IP of the client)

                                        Then climb up to TcpServer.

                                        Sorry

                                        D 1 Reply Last reply 2 Apr 2019, 17:36
                                        1
                                        • C CP71
                                          2 Apr 2019, 17:28

                                          @Dooham
                                          Ok,
                                          When we have some problems we say, “the computer has always reason”, well almost always.
                                          I’m joking ;)

                                          I already done a TCP Server but I took another road and I hadn't got special problems, so now I haven’t ideas. :(

                                          If I can, I suggest you to solve one problem at a time, I would start at the end, as per QtcpSocket, to try to understand why readyRead seems not working I should check the following checks:

                                          • Check with Wireshark or other tools if TCP packets arrive to your device
                                          • Check by debug text info about QTcpSocket that you have created (e.g. IP of the client)

                                          Then climb up to TcpServer.

                                          Sorry

                                          D Offline
                                          D Offline
                                          Dooham
                                          wrote on 2 Apr 2019, 17:36 last edited by
                                          #23

                                          @CP71 Dont worry, you are helpful. I will tried to find the trouble, I know that must be in my Code of the server, because in the first Code that I published in this thread I could do It. And in a simpler Code for just one connection server-client It also worked.

                                          1 Reply Last reply
                                          1

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                                          1 Apr 2019, 20:42

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