qtLoggingMessageHandler.cpp

void loggingMessageHandler(QtMsgType type, const QMessageLogContext & context, const QString & msg)
{
    QString timeStr(QDateTime::currentDateTime().toString("dd-MM-yy HH:mm:ss:zzz"));
    QString contextString(QString("[%1  %2]").arg(context.file).arg(context.line));

    mutex.lock();

    QString level;
    if(logFile.isOpen())
    {
        switch (type) {
        case QtInfoMsg:     level = QString("INF"); break;
        case QtDebugMsg:    level = QString("DEB"); break;
        case QtWarningMsg:  level = QString("WAR"); break;
        case QtCriticalMsg: level = QString("CRT"); break;
        case QtFatalMsg:    level = QString("FTL"); break;
        }
        QTextStream stream(&logFile);
        stream << timeStr << " " << contextString << "\t"  << level << "\t"  << msg << endl;
        stream.flush();
    }

#if defined(Q_OS_WIN)
    OutputDebugString(reinterpret_cast<const wchar_t *>(level.append(' ' + msg + '\n').utf16()));
#elif defined(Q_OS_ANDROID)
    android_default_message_handler(type, context, level.append(" " + msg));
#else   // MACX || IOS || LINUX
    fprintf(stderr, "%s\n", level.append(" " + msg).toLocal8Bit().constData());
#endif
      mutex.unlock();
}