Question

I am trying to write a program that will create a text file and write a stream of characters that I read from a serial port. I am just trying to understand how I can get the code to continuously write the data and not overwrite the previously written data because I will need it to keep every character sent. I wrote this code as a test but I can’t get it to continuously write the text. It writes it once and then stops.

#include <QFile>
#include <QTextStream>
int main() {
int test = 0;
while(test < 2){
QString filename = "Data.txt";
QFile file(filename);
if (file.open(QIODevice::ReadWrite)) {
    QTextStream stream(&file);
    stream << "one thing to test" << endl;
    test++;
  }
 }
}

Anyone have any suggestions?

-Thanks

Answer 1

By default, opening with QIODevice::ReadWrite will truncate the file on write. According to the documentation, QIODevice::Append will open the file for writing at the end of the file.

If you really want to both read and write, you could QIODevice::seek() to the end of the file before writing.