<para>Applications must always fill in the
<structfield>count</structfield>,
-<structfield>ctrl_class</structfield>,
+<structfield>which</structfield>,
<structfield>controls</structfield> and
<structfield>reserved</structfield> fields of &v4l2-ext-controls;, and
initialize the &v4l2-ext-control; array pointed to by the
value or if an error is returned.</para>
<para>When the <structfield>id</structfield> or
-<structfield>ctrl_class</structfield> is invalid drivers return an
+<structfield>which</structfield> is invalid drivers return an
&EINVAL;. When the value is out of bounds drivers can choose to take
the closest valid value or return an &ERANGE;, whatever seems more
appropriate. In the first case the new value is set in
<listitem>
<para>The &v4l2-ext-control; <structfield>id</structfield>
is invalid, the &v4l2-ext-controls;
-<structfield>ctrl_class</structfield> is invalid, or the &v4l2-ext-control;
+<structfield>which</structfield> is invalid, or the &v4l2-ext-control;
<structfield>value</structfield> was inappropriate (e.g. the given menu
index is not supported by the driver). This error code is
also returned by the <constant>VIDIOC_S_EXT_CTRLS</constant> and