- If an error occurs during the callback invocation, the callback should
- return a negative error number. If it wants other callbacks that match the
- same rule to be called, it should return 0. Otherwise it should return a
+ The message <parameter>m</parameter> passed to the callback is only borrowed, that is, the callback should not
+ call <citerefentry><refentrytitle>sd_bus_message_unref</refentrytitle><manvolnum>3</manvolnum></citerefentry> on
+ it. If the callback wants to hold on to the message beyond the lifetime of the callback, it needs to call
+ <citerefentry><refentrytitle>sd_bus_message_ref</refentrytitle><manvolnum>3</manvolnum></citerefentry> to create
+ a new reference.
+ </para>
+
+ <para>
+ If an error occurs during the callback invocation, the callback should return a negative error number. If it
+ wants other callbacks that match the same rule to be called, it should return 0. Otherwise it should return a