The structure is not freed, just its contents.

svn path=/trunk/vorbis/; revision=12897

doc/vorbisfile/ov_clear.html

@@ -37,7 +37,7 @@ int ov_clear(OggVorbis_File *vf);
 <dl>
 <dt><i>vf</i></dt>
 <dd>A pointer to the OggVorbis_File structure--this is used for ALL the externally visible libvorbisfile
-functions.  After <tt>ov_clear</tt> has been called, the structure is deallocated and can no longer be used.</dd>
+functions.  After <tt>ov_clear</tt> has been called, the contents of this structure are deallocated, and it can no longer be used.</dd>
 </dl>