+ <para>To destroy an event source object use
+ <citerefentry><refentrytitle>sd_event_source_unref</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+ but note that the event source is only removed from the event loop
+ when all references to the event source are dropped. To make sure
+ an event source does not fire anymore, even when there's still a
+ reference to it kept, consider setting the event source to
+ <constant>SD_EVENT_OFF</constant> with
+ <citerefentry><refentrytitle>sd_event_source_set_enabled</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para>
+
+ <para>If the second parameter of
+ <function>sd_event_add_child()</function> is passed as NULL no
+ reference to the event source object is returned. In this case the
+ event source is considered "floating", and will be destroyed
+ implicitly when the event loop itself is destroyed.</para>
+
+ <para>Note that the <parameter>handler</parameter> function is
+ invoked at a time where the child process is not reaped yet (and
+ thus still is exposed as a zombie process by the kernel). However,
+ the child will be reaped automatically after the function
+ returns. Child processes for which no child process state change
+ event sources are installed will not be reaped by the event loop
+ implementation.</para>
+
+ <para>If both a child process state change event source and a
+ <constant>SIGCHLD</constant> signal event source is installed in
+ the same event loop, the configured event source priorities decide
+ which event source is dispatched first. If the signal handler is
+ processed first, it should leave the child processes for which
+ child process state change event sources are installed unreaped.</para>
+