LINUX下如何控制小键盘灯的亮和灭

http://topic.csdn.net/u/20081113/10/adfdd896-e7b3-437e-8e1e-9dbbeffb6ff3.html

我有一个例子是让三个灯不断的在闪的

例子如下：
#include <stdio.h>
#include <fcntl.h>
#include <unistd.h>
#include <signal.h>
#include <sys/stat.h>
#include <linux/kd.h>
#include <sys/types.h>
#include <sys/ioctl.h>
#define ERROR -1
int fd; /* File descriptor for console (/dev/tty/) */
void sighandler(int signum);
void main()
{
  int i;
  /* To be used as the fd in ioctl(). */
  if ((fd = open("/dev/console", O_NOCTTY)) == ERROR)
{
perror("open");
exit(ERROR);
}
  signal(SIGINT, sighandler);
  signal(SIGTERM, sighandler);
  signal(SIGQUIT, sighandler);
  signal(SIGTSTP, sighandler);
  printf("w00w00!\n\n");
  printf("To exit hit Control-C.\n");
while (1) 
  {
for (i = 0x01; i <= 0x04; i++) 
{
/* We do this because there is no LED for 0x03. */
if (i == 0x03) continue;
usleep(50000);
if ((ioctl(fd, KDSETLED, i)) == ERROR) {
perror("ioctl");
close(fd);
exit(ERROR);
}
}
  }
close(fd);
}
void sighandler(int signum)
{
  /* Turn off all leds. No LED == 0x0. */
if ((ioctl(fd, KDSETLED, 0x0)) == ERROR) 
  {
  perror("ioctl");
  close(fd);
  exit(ERROR);
  }
printf("\nw00w00!\n");
close(fd);
exit(0);
}

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#define KDGETLED    0x4B31    /* return current led state */
#define KDSETLED    0x4B32    /* set led state [lights, not flags] */
#define     LED_SCR        0x01    /* scroll lock led */
#define     LED_NUM        0x02    /* num lock led */
#define     LED_CAP        0x04    /* caps lock led */

每次切换前，记录当前scroll 、num 和caps 状态，即是否打开，然后
ioctl(fd, KDSETLED, 0x0)) 关闭所有LED，
然后点亮当前需要的key，其它的key根据上次状态恢复即可

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