How to use log4cplus in a custom singleton class

Question

I configure this log4cplus' static object in my custom class LogCp's constructor function,and in this constructor I do write some test code and it can export the informations to a designated file correctly,but when I call the GetInstance fun ction,which will return the only object,it can't write the log and the error message is cannot find the appender of filelogger.It confuse me,I had called the doConfigure() in constructor and the logger had been configured correctly,why I still got this error in main function?Do I need to call doConfigure() everytime before I write log? Following is my code:

class LogCp
{
public:

    ~LogCp();
    static LogCp& GetInstance();
    static Logger _logger;

private:
    LogCp();
    LogCp(const LogCp&) = delete;
    void operator =(LogCp const&);

};

Logger LogCp::_logger = log4cplus::Logger::getInstance(LOG4CPLUS_TEXT("filelogger"));
//Logger LogCp::_logger = log4cplus::Logger::getRoot(); 

LogCp::LogCp()
{
    log4cplus::Initializer initializer;
    try {
        PropertyConfigurator::doConfigure(LOG4CPLUS_TEXT("E:\\log4cplus.properties"));
        //_logger = log4cplus::Logger::getInstance(LOG4CPLUS_TEXT("filelogger"));
        LOG4CPLUS_WARN(_logger, LOG4CPLUS_TEXT("logging...."));
    }
    catch (...) {
        LOG4CPLUS_FATAL(_logger, LOG4CPLUS_TEXT("Exception occured..."));
    }
}

LogCp& LogCp::GetInstance()
{
    static LogCp vLogCp;
    return vLogCp;
}

LogCp::~LogCp()
{

}

the main function:

void logInitial()
{
    LogCp::GetInstance();

}

int main(int argc, wchar_t* argv[])
{
    logInitial();
    LOG4CPLUS_WARN(LogCp::GetInstance()._logger, LOG4CPLUS_TEXT("test"));
}

It can log correctly in constructor function,but it won't log "test" in main() function unless I add doConfigure() function again before LOG4CPLUS_WARN.why?

score 1 · Accepted Answer · answered Nov 29 '16 at 11:17

1

You need to configure the library before you try to use it. The doConfigure() function sets up appenders without which there will be no output.

Using log4cplus::Initializer initializer; in your ctor is wrong. It will initialize the library and deinitialize it at the end of the constructor. The initializer object must live throughout the use of the library.

answered Nov 29 '16 at 11:17

wilx

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Thanks for your anwser,I jsut removed the “log4cplus::Initializer initializer”,then everything is OK,there is no assert or errormsg,but all the records will be logged at the end of my process.But when I compiled my program,it warned me that I'm not using a DLL C CRT so I need to call initialize() once before I use it,what should I do to use log4cplus in a singleton class?@wilx – TimGallin Nov 30 '16 at 09:24

How to use log4cplus in a custom singleton class

1 Answers1