http://bugs.winehq.org/show_bug.cgi?id=24859
--- Comment #4 from Vincent Povirk madewokherd@gmail.com 2011-10-06 10:37:07 CDT --- I think if you set *num to 0, this would be an OK change to make.
The correct solution would be to implement this function of course (based on metadata stuff in WIC, also unimplemented). I don't know how to do that yet.