How to store log message in file using log4qt library ?

[Qt embedded developer]

I am using log4qt a open source library for C++ logging. i want to store log message in file using this library and on off feature of this library . So i need sample example to achieve this.

I am able to get print on console using below code

    Log4Qt::LogManager::rootLogger();
    Log4Qt::TTCCLayout *p_layout = new Log4Qt::TTCCLayout();

    p_layout->setName(QLatin1String("My Layout"));
    p_layout->activateOptions();
    // Create an appender
    Log4Qt::ConsoleAppender *p_appender = new Log4Qt::ConsoleAppender(p_layout, Log4Qt::ConsoleAppender::STDOUT_TARGET);
    p_appender->setName(QLatin1String("My Appender"));
    p_appender->activateOptions();
    // Set appender on root logger
    Log4Qt::Logger::rootLogger()->addAppender(p_appender);

    Log4Qt::Logger::logger(QLatin1String("My Logger"))->info("Hello World!");

[jsulm]

@Qt-embedded-developer said in How to store log message in file using log4qt library ?:

log4j.rootLogger=INFO, file

Shouldn't it be FILE, not file?
Compare your properties to https://www.tutorialspoint.com/log4j/log4j_logging_files.htm

[jsulm]

@Qt-embedded-developer What about http://log4qt.sourceforge.net/html/class_log4_qt_1_1_rolling_file_appender.html or http://log4qt.sourceforge.net/html/class_log4_qt_1_1_daily_rolling_file_appender.html ? All in the documentation which you should read...

[Qt embedded developer]

@jsulm Thanks for help. your help encouraged me to achieve something which i need.

I have implemented below code but i am getting error :

ERROR Log4Qt::PropertyConfigurator - Missing appender definition for appender named 'file'

How to resolve this error and How to add "Hello wold" in logging file as warning ?

My log4qt.properties contents are

log4j.rootLogger=INFO, file

lo4j.appender.file = org.apache.log4j.FileAppender

lo4j.appender.file.File = /home/mangal/WORK_S/Project/24july21_log/50/trunk/logging.log

lo4j.appender.file.MaxFileSize=3MB

lo4j.appender.file.MaxBackupIndex=2

 lo4j.appender.file.layout=org.apache.log4j.PatternLayout
 lo4j.appender.file.layout.ConversionPattern=%d{yyyy-mm-dd HH:mm:ss} %-5p %c{1}:%L - %m%n

My main file is

    QApplication a(argc, argv);

    // Configure with the specified configuration file
    QString configFile = "/home/mangal/WORK_S/Project/24july21_log/50/trunk/log4qt.properties";
        //QString configFile = "D:/ExecuteProgram/TagDataMonitor/trunk/output/config/log4qt.properties";
        if (QFile::exists(configFile))
        {
            Log4Qt::PropertyConfigurator::configureAndWatch(configFile);
        }

        Log4Qt::BasicConfigurator::configure();
        //log pattern
        Log4Qt::Logger *log = Log4Qt::Logger::rootLogger();
        Log4Qt::PatternLayout *lay = new Log4Qt::PatternLayout(Log4Qt::PatternLayout::TTCC_CONVERSION_PATTERN);
        lay->setConversionPattern("%-d{yyyy-MM-dd HH:mm:ss} [%c]-[%p] %m%n");


        Log4Qt::FileAppender *fileappender = new Log4Qt::FileAppender(lay,"/home/mangal/WORK_S/Project/24july21_log/50/trunk/log4qt.properties");
        fileappender->setAppendFile(true);
        fileappender->activateOptions();
        fileappender->setEncoding(QTextCodec::codecForName("UTF-8"));
        log->addAppender(fileappender);

        //delete dirtmp;
        log->deleteLater();



    return a.exec();
    //      Qt application is running, events are generated and sent to the widgets of the application.

[jsulm]

@Qt-embedded-developer said in How to store log message in file using log4qt library ?:

log4j.rootLogger=INFO, file

Shouldn't it be FILE, not file?
Compare your properties to https://www.tutorialspoint.com/log4j/log4j_logging_files.htm

[Qt embedded developer]

@jsulm

Thanks for help. i get the output which i want.

WHEN i am replacing with file print come into file with below print come 2 time in application output window with out put

25 [0x0000000000ba7740] ERROR Log4Qt::PropertyConfigurator - Missing appender definition for appender named 'FILE' (Log4Qt::PropertyConfigurator::CONFIGURATOR_MISSING_APPENDER_ERROR, 24)

24 [0x0000000002571d80] INFO My Logger - Hello World!

My code is :

   QApplication a(argc, argv);
    Log4Qt::BasicConfigurator::configure();
    Log4Qt::PropertyConfigurator::configure("/home/mangal/WORK_S/Project/24july21_log/50/trunk/log4qt.properties");

    // Configure with the specified configuration file
        QString configFile = "/home/mangal/WORK_S/Project/24july21_log/50/trunk/log4qt.properties";

            if (QFile::exists(configFile))
            {
                Log4Qt::PropertyConfigurator::configureAndWatch(configFile);
            }

            Log4Qt::BasicConfigurator::configure();
            //log pattern
            Log4Qt::Logger *log = Log4Qt::Logger::rootLogger();
            Log4Qt::PatternLayout *lay = new Log4Qt::PatternLayout(Log4Qt::PatternLayout::TTCC_CONVERSION_PATTERN);
            lay->setConversionPattern("%-d{yyyy-MM-dd HH:mm:ss} [%c]-[%p] %m%n");


            Log4Qt::FileAppender *fileappender = new Log4Qt::FileAppender(lay,"/home/mangal/WORK_S/Project/24july21_log/50/trunk/logging.log");
            fileappender->setAppendFile(true);
            fileappender->activateOptions();
            fileappender->setEncoding(QTextCodec::codecForName("UTF-8"));
            log->addAppender(fileappender);

            Log4Qt::Logger::logger(QLatin1String("My Logger"))->info("Hello World!");
            //delete dirtmp;

            log->deleteLater();