About QFile and QDatastream...

streetsoul

I try save data to text file using QFile and QDatastream.
For this function, I add the source code like below.

void MainWindow::on_saveButton_clicked() {
  QString fileName = QFileDialog::getSaveFileName(this, tr("Export File"), "", tr("Text (*.txt)::All Files (*)"));
  if(fileName.isEmpty())  return;
    else {
        QFile file(fileName);
        if(!file.open(QIODevice::WriteOnly)) {
            QMessageBox::information(this, tr("Unable to open file"), file.errorString());
            return;
        }
        QDataStream out(&file);
        out.setVersion(QDataStream::Qt_5_10);
        out << "test";
    }
}

I hope to just exist "text" message in text file.
But the result is below...
"NUL NUL NUL ENO test NUL"

What is the NUL, ENO?? And how can I remove this message??

jsulm

@streetsoul If you want to write text you should use http://doc.qt.io/qt-5/qtextstream.html

J.Hilk

@streetsoul
Hi, what you see there before the text is probably what QDataStream made out of the QString header, so that you can read it from the file back into a QString without problems.

Anyway, if you want to write a Human-readable textfile, than QDataStream is the wrong choice.

Use QTextStream, and open the file with QIODevice::Text flag.

Rondog

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