How I listen serial port with writing client code?

elypheldia

I am working on communication of virtual serial ports. I opened and wrote the data to the virtual serial port. Then, I listened with using socket.

cat /dev/tnt0

But now, I want to listen the tnt0 serial port over qt client code. How can I do that? If you give some examples, it would be nice.
main.cpp

#include <QCoreApplication>
#include "myserialport.h"
int main(int argc, char *argv[])
{
    QCoreApplication a(argc, argv);

    MySerialPort s;
    s.openSerialPort();

    return a.exec();
}

myserialport.h

#ifndef MYSERIALPORT_H
#define MYSERIALPORT_H

#include <QObject>
#include <QSerialPort>

class MySerialPort : public QObject
{
    Q_OBJECT
public:
    explicit MySerialPort(QObject *parent = nullptr);
    void openSerialPort();
    void closeSerialPort();
    void writeData(const QByteArray &);


signals:

public slots:
    void readData();
    void handleError(QSerialPort::SerialPortError);
private:
    QSerialPort *serial;
};

#endif // MYSERIALPORT_H

myserialport.cpp

#include "myserialport.h"
#include <QSerialPort>
#include <QDebug>
#include <QSerialPortInfo>
MySerialPort::MySerialPort(QObject *parent) : QObject(parent)
{
    serial=new QSerialPort(this);
    connect(serial,SIGNAL(readyRead()),this,SLOT(readData()));
    connect(serial, SIGNAL(error(QSerialPort::SerialPortError)), this,
    SLOT(handleError(QSerialPort::SerialPortError)));

}
void MySerialPort::openSerialPort()
{
    serial->setPortName("/dev/tnt0");
    serial->setBaudRate(QSerialPort::Baud9600);
    serial->setDataBits(QSerialPort::Data8);
    serial->setFlowControl(QSerialPort::NoFlowControl);
    serial->setStopBits(QSerialPort::OneStop);
    serial->setParity(QSerialPort::NoParity);
    if(serial->open(QIODevice::ReadWrite))
    {
        qDebug()<<"opened";
        QByteArray data="hello";
        writeData(data);

    }
    else
    {
        qDebug()<<QSerialPort::PermissionError;
    }

}
void MySerialPort::closeSerialPort()
{
    if(serial->isOpen())
    {
        serial->close();
    }
}
void MySerialPort::writeData(const QByteArray &data)
{
    qDebug() << "Bytes Written:" << serial->write(data);

}
void MySerialPort::readData()
{
    serial->readAll();

}
void MySerialPort::handleError(QSerialPort::SerialPortError error)
{
    if (error == QSerialPort::NoError) {
        qDebug()<<"no error";
    }
}

KroMignon

@elypheldia What is the problem with the code you have submitted?

NOTE: I would use new connect syntax to avoid failures about signals/slots not existing:

//OLD syntax
connect(serial,SIGNAL(readyRead()), this,SLOT(readData()));
connect(serial, SIGNAL(error(QSerialPort::SerialPortError)), this,
    SLOT(handleError(QSerialPort::SerialPortError)));

// NEW syntax
connect(serial, &QSerialPort::readyRead, this, &MySerialPort::readData);
connect(serial, &QSerialPort::error, this, &MySerialPort::handleError);

elypheldia

@KroMignon Thx for editing. There is no problem that I have submitted. I just wanna read tnt0 serial port by writing client code, not using socket. (That's why I submitted the code that I listen with socket.)

KroMignon

@elypheldia said in How I listen serial port with writing client code?:

I just wanna read tnt0 serial port by writing client code, not using socket. (That's why I submitted the code that I listen with socket.)

I don't understand this, which socket are you talking about?
You code is base on QSerialPort, so you are using serial port interface not any socket.

void MySerialPort::readData()
{
    QByteArray data = serial->readAll();
    QDebug() << "Received" << data.size() << "bytes:" << QString(data.toHex(':'));
}

elypheldia

@KroMignon Sorry if used the wrong term. I am new on qt. I wanted to indicate that I read the data I wrote to the tnt0 serial port from terminal with using cat /dev/tnt0. But How can I do this with client code instead of reading from terminal. I just wanna open the tnt1 serial port from code., and I wanna read from there.

KroMignon

@elypheldia said in How I listen serial port with writing client code?:

Sorry if used the wrong term. I am new on qt. I wanted to indicate that I read the data I wrote to the tnt0 serial port from terminal with using cat /dev/tnt0. But How can I do this with client code instead of reading from terminal. I just wanna open the tnt1 serial port from code., and I wanna read from there.

You are confusing to me.
Do you want to use /dev/tnt0 or /dev/tnt1?

With the code example you have provided, you are writing hello on serial device /dev/tnt0. Is this working?

You have defined a slot MySerialPort::readData() , which is called when data are ready to be read from serial port.
I have proposed you some changes to display debug message when slot is called. Is this slot called?

I don't know:

what kind of device is connected to this serial port?
if the serial port configuration is correct according to attached device?
the attached device communication protocol: It is a binary or text protocol? Are carriage return or line feed required?