qDebug Qt console application to output to Qt Crea

Question

How do I use qDebug in a Qt console application to output to the Qt Creator "application output" window? Currently qDebug writes to the console window which interferes with the non-debug output.

Using qDebug in a Qt GUI app outputs to application output window by default.

Answer 1

You can either output everything to console or everything to Qt Creator's Application Output panel.

For sake of completeness: If you want to have all the output in the panel instead of console you can uncheck "Run in terminal" in Project->Run settings.

Answer 2

To redirect QDebug to multiple places, you might have to write some code, maybe like this:

QList<QtMsgHandler> messageHandlers_;

static void messageDispatcher(QtMsgType type, const char *msg)
{
  foreach (QtMsgHandler callback, ::messageHandlers_)
    callback(type, msg);
}

static void messageLogger(QtMsgType type, const char *msg)
{
  QString output;
  switch (type) {
  case QtDebugMsg:    output = QString("mesage: %1\n").arg(msg); break;
  case QtWarningMsg:  output = QString("warning: %1\n").arg(msg); break;
  case QtCriticalMsg: output = QString("critical: %1\n").arg(msg); break;
  case QtFatalMsg:    output = QString("fatal: %1\n").arg(msg); break;
  default: return;
  }

  QFile file("log.txt");
  if (file.open(QIODevice::WriteOnly | QIODevice::Append))
    QTextStream(&file) << output;
}

int main()
{
  ...
  ::messageHandlers_.append(messageLogger)
  qInstallMsgHandler(messageDispatcher);
  ...
}