Re: accessing media_changed() for CDROMs
Jens Axboe (axboe@image.dk)
Thu, 04 Feb 1999 22:46:11 +0100
"D.A. Harris" wrote:
>
> Hi,
>
> I would have sent this to the linux-c-programming list, but it appears to
> be down.
>
> I'm pretty new to programming on Linux, especially when it involves trying
> to interface with the kernel. I have a test program attached that basically
> just trying to get status of media_changed(), so I can tell if a CDROM has
> changed. The grand plan is to set up a daemon that can monitor media
> changed events for various types of media, and do operations like automatic
> mounting, kind of like mediad on IRIX. But right now I don't have much
> clue. So can anyone point me in the right direction? Am I even doing the
> ioctl() call right? One thing for sure is that the call to media_changed()
> generates a segmetation violation.
The correct way to use the ioctl, would be something like this :
changed = ioctl(drive, CDROM_MEDIA_CHANGED, CDSL_CURRENT);
And that is the only way you can do it. There's no way you can retrieve
the info by trying to call media_changed() - userspace programs can't
access kernelspace functions like that. Hey, that's one of the reasons
for ioctl!
--
* Jens Axboe <axboe@image.dk>
* Linux CD-ROM Maintainer
* "The only thing that interferes with my
* learning is my education." -- A. Einstein
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