Qt Serial Communication in Mac OS Buffer Problem

[kangherr]

I tried run samples of qt serial blocking master on Mac OS Sierra, I tried to loop the serial line (loopback) but I got problem there the data going bad.
I tried to add flush command but still problem.

How to fix it?

[Christian Ehrlicher]

Make sure to read old data from the serial device after you've opened it by calling readAll() - it may be that the serial port has some data which was not yet read.

[kangherr]

I have added readAll() after opened the port but problem still in there, also I tried to modified timeout time for ready read but not help.

while (!m_quit) {
        //![6] //! [7]
        if (currentPortNameChanged) {
            serial.close();
            serial.setPortName(currentPortName);

            if (!serial.open(QIODevice::ReadWrite)) {
                emit error(tr("Can't open %1, error code %2")
                           .arg(m_portName).arg(serial.error()));
                return;
            }
            //I added this one
            QByteArray responseData = serial.readAll();
            while (serial.waitForReadyRead(500))
                responseData += serial.readAll();
        }
        //! [7] //! [8]
        // write request
        const QByteArray requestData = currentRequest.toUtf8();
        serial.write(requestData);
        if (serial.waitForBytesWritten(m_waitTimeout)) {
            //! [8] //! [10]
            // read response
            if (serial.waitForReadyRead(currentWaitTimeout)) {
                QByteArray responseData = serial.readAll();
                while (serial.waitForReadyRead(500)) //and modified this time
                    responseData += serial.readAll();

                const QString response = QString::fromUtf8(responseData);
                //! [12]
                emit this->response(response);
                //! [10] //! [11] //! [12]

[kangherr]

I've tested with two serial port (no loopback communication) but the problem still in there.

This problem not appear when I use windows operating system.

[SGaist]

Hi,

What type of serial port are you using ?