#include <fcntl.h>
#include <linux/cdrom.h>
#include <stdio.h>
#include <sys/ioctl.h>
#include <unistd.h>

int main(void)
{
    int fd = open("/dev/cdrom", O_RDONLY | O_NONBLOCK);
    if (fd == -1)
    {
        printf("Failed opening CD-ROM.\n");
        return -1;
    }
    
    if (!ioctl(fd, CDROMEJECT, NULL))
        printf("Ejected CD-ROM successfully.\n");
    else
        printf("Failed ejecting CD-ROM.\n");
    close(fd);
    return 0;
}

由於open光驅時，可能光驅中沒有光盤，因此需要使用O_NONBLOCK選項，否則open會失敗（系統默認為我們打開這個光驅的目的是查看光盤上的文件）

打開光驅，5秒後再自動關閉光驅的程序：
#include <fcntl.h>
#include <linux/cdrom.h>
#include <stdio.h>
#include <sys/ioctl.h>
#include <unistd.h>

int main(void)
{
    int fd = open("/dev/cdrom", O_RDONLY | O_NONBLOCK);
    if (fd == -1)
    {
        printf("Failed opening CD-ROM.\n");
        return -1;
    }
   
    if (!ioctl(fd, CDROMEJECT, NULL))
        printf("Ejected CD-ROM successfully.\n");
    else
        printf("Failed ejecting CD-ROM.\n");

    sleep(5);
    if (!ioctl(fd, CDROMCLOSETRAY, NULL))
        printf("Closed CD-ROM successfully.\n");
    else
        printf("Failed closing CD-ROM.\n");

    close(fd);
    return 0;
}

[octopus@pc3 cdrom]$ ./cdrom
Ejected CD-ROM successfully.
Closed CD-ROM successfully.
[octopus@pc3 cdrom]$