QSerialPort crash on write()

[MichaelR]

Hello,

I find that this code runs fine in Debug mode but in Release mode causes my program to crash a few seconds after opening.

If remove the line that writes to the serial port then it doesn't crash.

I can't figure out why it is crashing!

MyClass::MyClass()
{
    // Serial port connection
    m_serialPort = new QSerialPort(this);
    connect(m_serialPort, &QSerialPort::readyRead, this, &MyClass::readSerialData);
    openSerialPort();
}

void MyClass::openSerialPort()
{
    QString portName = "";

    const QList<QSerialPortInfo> infos = QSerialPortInfo::availablePorts();
    for (const QSerialPortInfo &info : infos) {
        if (info.isBusy() == false) {
            portName = info.portName();
        }
    }

    m_serialPort->setPortName(portName);
    if (m_serialPort->open(QIODevice::ReadWrite)) {
        // connected
    } else {
        qWarning() << "Cannot open serial port";
    }

    m_serialPort->write("TESTWRITE", 9);
}

[VRonin]

can you try replacing m_serialPort->write("TESTWRITE", 9); with

QTextStream portStream(m_serialPort);
portStream << "TESTWRITE";

[MichaelR]

Thanks for the suggestion VRonin.

I tried this but still causes program to crash after 10 or 15 seconds.

[SGaist]

Hi,

Can you show a stack trace ?

[VRonin]

@SGaist said in QSerialPort crash on write():

Can you show a stack trace ?

Can you get a meaningful stack trace in release mode?

BTW the problem does not appear to be in this snippet

[SGaist]

Indeed, it's harder. I somehow missed the "Release" part...

On a side note, it's pretty unusual to call write if the port opening failed.