Question

Is it possible to programmatically configure log4cpp?

I want to configure it as it would be configured by supplying the following config file.

appender root basic console
priority root DEBUG

Answer 1

Do you mean log4cpp from http://sourceforge.net/projects/log4cpp/ ?

The short answer is yes.

Here are some sample codes, and you can figure out more details based on its doc:

My codes are used to configure file-based log4cpp instance at run-time.

“priority” is ‘DEBUG’, …
“name” here is ‘root’
“layout” could be “%d{%Y-%m-%d %H:%M:%S}%c %x: %m%n”

// Create RollingFileAppender
log4cpp::Appender *rfileAppender = new log4cpp::RollingFileAppender(std::string(name),
        std::string(fileName),
        maxFileSize,
        maxBackupIndex,
        append,
        mode);

if (rfileAppender != NULL)
{
    // Create PatternLayout
    log4cpp::Layout *layout = new log4cpp::PatternLayout();

    if (layout != NULL)
    {
        try
        {
            // Set up Pattern
            ((log4cpp::PatternLayout *)layout)->setConversionPattern(std::string(layoutPattern));

            // Bind Layout to RollingFileAppender
            rfileAppender->setLayout(layout);

            category.setAdditivity(additivity);

            try
            {
                category.setPriority(log4cpp::Priority::getPriorityValue(std::string(priority)));
            }
            catch(std::invalid_argument &ia)
            {
                std::cerr << "Invalid Priority: "  << priority << std::endl;
                category.setPriority(log4cpp::Priority::INFO);
            }

            // Bind RollingFileAppender to Category
            category.addAppender(rfileAppender);

            return 0;
        }
        catch(log4cpp::ConfigureFailure &cf)
        {
            std::cerr << cf.what() << std::endl;
            return 1;
        }
    }
    else
    {
        std::cerr << "Cannot initialize PatternLayout" << std::endl;
        return 1;
    }
}