lua: update explanation about register_notification callback

Signed-off-by: Kentaro Hayashi <hayashi@clear-code.com>

diff --git a/src/collectd-lua.pod b/src/collectd-lua.pod
index 88aeda9d6fbca287e547c5f778d55f482094bc5a..272eb5f0a8af5b6c200168b5c9756953d445db54 100644 (file)
--- a/src/collectd-lua.pod
+++ b/src/collectd-lua.pod
@@ -111,6 +111,11 @@ once for every after B<init functions>.
 These are used to clean-up the internal state. They are called once for
  every shutting down phase.
 
+=item notification functions
+
+These are used to receive a PUTNOTIF event. They are called once for
+ every notification phase.
+
 =back
 
 =head1 FUNCTIONS
@@ -150,6 +155,12 @@ table of values.
 Function to register shutdown callbacks.
 The callback function will be called without arguments.
 
+=item register_notification(callback)
+
+Function to register notification callbacks.
+The callback function will be called with one argument passed, which will be a
+table of values.
+
 =item log_error, log_warning, log_notice, log_info, log_debug(I<message>)
 
 Log a message with the specified severity.