+ <para><function>sd_session_get_state()</function> may
+ be used to determine the state of the session
+ identified by the specified session identifier. The
+ following states are currently known:
+ <literal>online</literal> (session logged in, but
+ session not active, i.e. not in the foreground),
+ <literal>active</literal> (session logged in and
+ active, i.e. in the foreground),
+ <literal>closing</literal> (session nominally logged
+ out, but some processes belonging to it are still
+ around). In the future additional states might be
+ defined, client code should be written to be robust in
+ regards to additional state strings being
+ returned. This function is a more generic version of
+ <function>sd_session_is_active()</function>. The returned
+ string needs to be freed with the libc
+ <citerefentry><refentrytitle>free</refentrytitle><manvolnum>3</manvolnum></citerefentry>
+ call after use.</para>
+