Torbjxrn Kristoffersen wrote:
> I'm trying to make a program that simply ejects the CD-ROM. The reason
> why is that I'd like to learn more about the ioctl() call.
>
> Maybe I've misunderstood everything, but here's my code which doesn't
> work:
>
> FILE *fd = fopen("/dev/cdrom", "w");
The first argument to ioctl() must be a descriptor (an integer), as
returned from open(), not an ANSI stream (`FILE *').
Also, trying to open /dev/cdrom for writing is likely to fail.
> int x;
>
> ioctl (fd, CDROMEJECT, &x);
>
> (I'm not really sure why I'm using 'x', but I saw it being used in
> another example and I saw that
> ioctl() took a third argument also)
The CDROMEJECT ioctl() doesn't use the third argument, so you can just
pass zero.
The following program works fine for me.
--
Glynn Clements <[EMAIL PROTECTED]>
#include <unistd.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include <linux/cdrom.h>
#include <stdio.h>
int main(void)
{
int fd = open("/dev/cdrom", O_RDONLY);
if (fd < 0)
{
perror("open(\"/dev/cdrom\") failed");
return 1;
}
if (ioctl(fd, CDROMEJECT, 0) < 0)
{
perror("ioctl(CDROMEJECT) failed");
return 1;
}
return 0;
}
