to all the
libvorbisfile functions.  Unlike <a
href="ov_fopen.html">ov_fopen()</a> and <a
href="ov_open.html">ov_open()</a>, ov_open_callbacks() may be used to
instruct vorbisfile to either automatically close or not to close the
file/data access handle in <a href="ov_clear.html">ov_clear()</a>.
Automatic closure is disabled by passing NULL as the close callback,
or using one of the predefined callback sets that specify a NULL close
callback.  The application is responsible for closing a file when a
call to