QFile ignoring last newline

Question

I'm using Qt to read a file

  std::vector<QString> text;

  QFile f(file);
  if (f.open(QFile::ReadWrite | QFile::Text) == false)
    throw my_exception();

  QTextStream in(&f);
  QString line;
  while(!in.atEnd()) {
    line = in.readLine();

    text.push_back(line);
  }
  f.close();

the problem with this approach is: I can't read extra newlines at the end of the file.

Suppose I have the following text file

Hello world\r\n
\r\n

I'm unable to get an empty string for the last \r\n line. How can I solve this?

score 0 · Answer 1 · answered Jul 13 '16 at 09:56

0

I think the newlines will be stripped. See Qt documentation of QTextStream.

You have to use readAll() or if newline is empty add '\n\r' by yourself.

answered Jul 13 '16 at 09:56

Kombinator

107
6

Wum · Accepted Answer · 2016-07-13T10:58:38.670

According to http://doc.qt.io/qt-4.8/qtextstream.html#readLine \r\n are always getting trimmed. So you will miss them in every read line. You could:

a) Add line terminators to the read strings after having used readLine()

b) Use QFiles.readLine() to read into a QByteArray which doesn't touch the read bytes:

while (!f.atEnd()) {
    QByteArray line = f.readLine();
    process_line(line);
}

c) Use another approach for reading the file, e.g. std::istream. See http://www.cplusplus.com/reference/istream/istream/getline/ for the equivalent getline.

QFile ignoring last newline

2 Answers2