qt binary file writing and reading

Question

void write(QString filename) {
  QChar ch('b');
  QFile mfile(filename);
  if (!mfile.open(QFile::WriteOnly) {
    qDebug() << "Could not open file for writing";
    return;
  }
  QDataStream out(&mfile);
  out.setVersion(QDataStream::Qt_4_8);
  out << ch;
  mfile.close();
}

open binary file and writing 'b'(binary)

void read(QString filename) {
  QFile mfile(filename);
  if (!mfile.open(QFile::ReadOnly)) {
    qDebug() << "Could not open file for reading";
    return;
  }
  QDataStream in(&mfile);
  in.setVersion(QDataStream::Qt_4_8);
  QChar mT;
  in >> mT;
  qDebug() << mT;
  mfile.close();
}

read but not mT='b'.if ch and mT variables are int always mT=4 why?How can i writing ch(binary file) and read from binary file

Sorry i was writing code in my mind. i opened and not change problem still — seniorc, Dec 16 '13 at 10:54
what are the values returned by in.status(), and out.status() — UmNyobe, Dec 16 '13 at 13:28
Can you properly write your question? You just paste some code and expect people to answer in a proper way? Also, how can this ever help someone else with similar problem? — Felipe Tonello, Aug 05 '15 at 15:24

Behrouz.M · Answer 1 · 2015-08-05T16:01:55.970

0

the 4 number is the length of your data. QDataStream store length of your data before it to indicate how many bytes need to read to gain the written data. your data has been written after it.

edited Aug 05 '15 at 16:01

answered Aug 05 '15 at 15:21

Behrouz.M

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qt binary file writing and reading

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