#include <stdio.h>
  #include <stdlib.h>
  #include <unistd.h>
  #include <fcntl.h>
  
  int main(void)
  {
  	int fd = open("/dev/watchdog", O_WRONLY);
  	int ret = 0;
  	if (fd == -1) {
  		perror("watchdog");
  		exit(EXIT_FAILURE);
  	}
  	while (1) {
  		ret = write(fd, "\0", 1);
  		if (ret != 1) {
  			ret = -1;
  			break;
  		}
  		sleep(10);
  	}
  	close(fd);
  	return ret;
  }