Trying to use mount()

[kenshi]

I'm trying to make a simple front-end for mpg123 for someone that will automatically mount the cd-rom and play all the mp3's on it. This is in unix in case that's not obvious. I'm stuck at the mount part. There are 4 parameters to the function (I think on some systems there are 5) and the first 3 are fairly straight forward, but there's a "data" struct that I can't seem to find much documentation on. The man page for mount() said the information should be in the man page for the corresponding man page for the file system, but there's nothing about it in man mount_cd9660. I've searched at programming sites and at Google and found nothing. I even looked in the source code for the mount command, but it seems to use another undocumented function. Does anyone know what goes into this struct? Thanks.