<para>Length of the mapped buffer. This must be the same
value as given to <function>mmap()</function> and returned by the
driver in the &v4l2-buffer; <structfield>length</structfield>
<para>Length of the mapped buffer. This must be the same
value as given to <function>mmap()</function> and returned by the
driver in the &v4l2-buffer; <structfield>length</structfield>