+
+ <para><function>sd_event_unrefp()</function> is similar to
+ <function>sd_event_unref()</function> but takes a pointer to a
+ pointer to an <type>sd_event</type> object. This call is useful in
+ conjunction with GCC's and LLVM's <ulink
+ url="https://gcc.gnu.org/onlinedocs/gcc/Common-Variable-Attributes.html">Clean-up
+ Variable Attribute</ulink>. Note that this function is defined as
+ inline function. Use a declaration like the following,
+ in order to allocate an event loop object that is freed
+ automatically as the code block is left:</para>
+
+ <programlisting>{
+ __attribute__((cleanup(sd_event_unrefp)) sd_event *event = NULL;
+ int r;
+ …
+ r = sd_event_default(&event);
+ if (r < 0)
+ fprintf(stderr, "Failed to allocate event loop: %s\n", strerror(-r));
+ …
+}</programlisting>
+
+ <para><function>sd_event_ref()</function>,
+ <function>sd_event_unref()</function> and
+ <function>sd_event_unrefp()</function> execute no operation if the
+ passed in event loop object is <constant>NULL</constant>.</para>
+
+ <para><function>sd_event_get_tid()</function> retrieves the thread
+ identifier ("TID") of the thread the specified event loop object
+ is associated with. This call is only supported for event loops
+ allocated with <function>sd_event_default()</function>, and
+ returns the identifier for the thread the event loop is the
+ default event loop of. See <citerefentry
+ project='man-pages'><refentrytitle>gettid</refentrytitle><manvolnum>2</manvolnum></citerefentry>
+ for more information on thread identifiers.</para>