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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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  • DoohamD Dooham

    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.

    DoohamD Offline
    DoohamD Offline
    Dooham
    wrote on last edited by
    #2

    @Dooham I also have this error: QObject: Cannot create children for a parent that is in a different thread.
    (Parent is QNativeSocketEngine(0x52fbc8), parent's thread is MyThread(0x5322f0), current thread is QThread(0x514de0)

    CP71C 1 Reply Last reply
    0
    • DoohamD Dooham

      @Dooham I also have this error: QObject: Cannot create children for a parent that is in a different thread.
      (Parent is QNativeSocketEngine(0x52fbc8), parent's thread is MyThread(0x5322f0), current thread is QThread(0x514de0)

      CP71C Offline
      CP71C Offline
      CP71
      wrote on last edited by CP71
      #3

      @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/

      DoohamD 1 Reply Last reply
      2
      • CP71C CP71

        @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/

        DoohamD Offline
        DoohamD Offline
        Dooham
        wrote on 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.

        CP71C 1 Reply Last reply
        1
        • DoohamD Dooham

          @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.

          CP71C Offline
          CP71C Offline
          CP71
          wrote on 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?

          DoohamD 1 Reply Last reply
          1
          • CP71C CP71

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

            DoohamD Offline
            DoohamD Offline
            Dooham
            wrote on 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.

            CP71C 1 Reply Last reply
            1
            • DoohamD Dooham

              @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.

              CP71C Offline
              CP71C Offline
              CP71
              wrote on last edited by CP71
              #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

              DoohamD 1 Reply Last reply
              1
              • CP71C CP71

                @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

                DoohamD Offline
                DoohamD Offline
                Dooham
                wrote on 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.

                CP71C 1 Reply Last reply
                1
                • DoohamD Dooham

                  @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.

                  CP71C Offline
                  CP71C Offline
                  CP71
                  wrote on 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.

                  DoohamD 1 Reply Last reply
                  1
                  • CP71C CP71

                    @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.

                    DoohamD Offline
                    DoohamD Offline
                    Dooham
                    wrote on 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

                    DoohamD CP71C 2 Replies Last reply
                    1
                    • SGaistS Offline
                      SGaistS Offline
                      SGaist
                      Lifetime Qt Champion
                      wrote on 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

                      DoohamD 1 Reply Last reply
                      2
                      • SGaistS SGaist

                        Hi,

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

                        DoohamD Offline
                        DoohamD Offline
                        Dooham
                        wrote on 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
                        • SGaistS Offline
                          SGaistS Offline
                          SGaist
                          Lifetime Qt Champion
                          wrote on 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

                          DoohamD 1 Reply Last reply
                          1
                          • SGaistS SGaist

                            What is your exact use of QSerialPort ?

                            DoohamD Offline
                            DoohamD Offline
                            Dooham
                            wrote on 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
                            • DoohamD Dooham

                              @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

                              DoohamD Offline
                              DoohamD Offline
                              Dooham
                              wrote on 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
                              • DoohamD Dooham

                                @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

                                CP71C Offline
                                CP71C Offline
                                CP71
                                wrote on last edited by CP71
                                #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
                                • DoohamD Dooham

                                  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.

                                  DoohamD Offline
                                  DoohamD Offline
                                  Dooham
                                  wrote on 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.

                                  DoohamD 1 Reply Last reply
                                  0
                                  • DoohamD Dooham

                                    @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.

                                    DoohamD Offline
                                    DoohamD Offline
                                    Dooham
                                    wrote on 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.

                                    CP71C 2 Replies Last reply
                                    1
                                    • DoohamD Dooham

                                      @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.

                                      CP71C Offline
                                      CP71C Offline
                                      CP71
                                      wrote on 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?

                                      DoohamD 1 Reply Last reply
                                      1
                                      • DoohamD Dooham

                                        @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.

                                        CP71C Offline
                                        CP71C Offline
                                        CP71
                                        wrote on 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
                                        • CP71C CP71

                                          @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?

                                          DoohamD Offline
                                          DoohamD Offline
                                          Dooham
                                          wrote on 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.

                                          CP71C 1 Reply Last reply
                                          1

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