Qt - Redirect qDebug output to file

log_redirect.cpp

#include <fstream>
 
using namespace std;
ofstream logfile;
 
void LogToFile(QtMsgType type, const char *msg) {
  QString datetime = QDateTime::currentDateTime().toString("yyyy.MM.dd hh:mm:ss");
  switch (type) {
    case QtDebugMsg:
      logfile << datetime.toString().toAscii().data() << " [Debug] " << msg << "\n";
      break;
    case QtCriticalMsg:
      logfile << datetime.toString().toAscii().data() << " [Critical] " << msg << "\n";
      break;
    case QtWarningMsg:
      logfile << datetime.toString().toAscii().data() << " [Warning] " << msg << "\n";
      break;
    case QtFatalMsg:
      logfile << datetime.toString().toAscii().data() <<  " [Fatal] " << msg << "\n";
      abort();
  }
}

logfile.open("/tmp/log.txt", ofstream::out | ofstream::app);

qInstallMsgHandler(LogToFile)