最简单的Linux关机命令程序

#include <signal.h>
#include <stdio.h>
#include <unistd.h>
#include <sys/reboot.h>

int main(int argc, char **argv)
{
    /* first disable all our signals */   
    sigset_t set;
    sigfillset(&set);
    sigprocmask(SIG_BLOCK, &set, NULL);

    /* send signals to all processes  _except_ pid 1 */
    printf("sending SIGTERM signal to all processes\n");
    kill(-1, SIGTERM);
    sync();
    sleep(3);
   
    printf("sending SIGKILL signal to all processes\n");
    kill(-1, SIGKILL);
    sync();
    sleep(3);
   
    /* shutdown */
    printf("system shutdown\n");
    sleep(2);
    reboot(RB_POWER_OFF);
}