Apache log4cxx is a logging framework for C++ patterned after Apache
log4j, which uses Apache Portable Runtime for most platform-specific
code and should be usable on any platform supported by APR. Apache
log4cxx is licensed under the Apache License, an open source license
certified by the Open Source Initiative.

Log4cxx has three main components: loggers, appenders and
layouts. These three types of components work together to enable
developers to log messages according to message type and level, and to
control at runtime how these messages are formatted and where they are
reported.