- <para>If the <literal>session</literal> parameter of
- any of these functions is passed as NULL the operation
- is executed for the session the calling process is a
- member of, if there is any.</para>
+ <para><function>sd_session_get_vt()</function>
+ may be used to determine the VT number of the
+ session identified by the specified session
+ identifier. This function will return an error if
+ the seat does not support VTs.</para>
+
+ <para>If the <varname>session</varname> parameter of
+ any of these functions is passed as
+ <constant>NULL</constant>, the operation is executed
+ for the session the calling process is a member of, if
+ there is any.</para>