Because Log4cxx is a logging library, we can't use it to output errors from the library itself.
There are several ways to activate internal debug logging: -# Setting the environment variable LOG4CXX_DEBUG to the value true -# If using a properties file, add the line log4j.debug=true to your file -# If using an XML file, add the debug=“true” attribute in the log4j.configuration element -# Configure the library programmatically by calling [LogLog::setInternalDebugging](@ref log4cxx.helpers.LogLog.setInternalDebugging)
To disable all messages, including error and warning messages, call [LogLog::setQuietMode(true)](@ref log4cxx.helpers.LogLog.setQuietMode).
All Log4cxx internal logging messages are sent to stderr, with each line prefixed by log4cxx:.