Question

I have a file which I would like to read again and again, to update a paramter in my code. but using QTextStream only reads the value once, and reads out 0 after that every time.

This is basically my code:

int main(){
    QString data;
    QFile Status;

    Status.setFileName("/home/user/status");
    Status.open(QIODevice::ReadOnly);

    QTextStream in(&Status);

    While(1){
        usleep(100);
        data = in.readLine();
        cout << "This is the status: " << data.toInt();
    }
return 0;
}

Problem is that it reads the “status” file correctly the fist time, but after that, it reads out “0”…Any thoughts of how I can read out this file again and again.

In additional info, my thought is to change the data of the file to update my app status, which is a number (int) between 0 and 100.

Thank you for any help, it is appreciated.. 🙂

Answer 1

Your code doesnt make sense. If you have successfully opened the file, then nobody will be able to open it for writing.

You can modify the loop :

While(1){
    usleep(100);
    if(status.open(QIODevice::ReadOnly) ){
        QbyteArray data = status.readline();//edited
        status.close();
        //read the first line (without newline)
        QString valueString = QString(data).section(0, '\n');
        cout << "This is the status: " << data.toInt();
    }
}

The if is a naive attempt to wait when if the file is opened by another program.