# Appendix I. Loggers and Listeners Phing has two related features to allow the build process to be monitored: listeners and loggers. I.1 Listeners A listener is alerted of the following events. - build started - build finished - target started - target finished - task started - task finishned - message logged These are used internally for various recording and housekeeping operations, however new listeners may registered on the command line through the `-listener` argument.