#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <unistd.h>
#include <pthread.h>
#include <sched.h>
#include <sys/ioctl.h>
#include <sys/types.h>
#include <sys/stat.h>

#include <linux/rtc.h>

#define RTC "/dev/rtc"

int run = 1;
#define NR_THREADS 3

void *func(void *dat)
{
	int fd = (int)dat;
	unsigned long data;


	while (run) {
		ioctl(fd, RTC_PIE_ON, 0);
		read(fd, &data, sizeof(data));
		ioctl(fd, RTC_PIE_OFF, 0);

		printf("%08lx\n",data);
	}
	return NULL;
}

int main(int argc, char **argv)
{
	int fd;
	int i;
	pthread_t t[NR_THREADS];

	if ((fd = open(RTC, O_RDONLY|O_NONBLOCK)) < 0) {
		perror(RTC);
		exit(0);
	}
	
	ioctl(fd, RTC_IRQP_SET, 1024);

	for (i=0; i < NR_THREADS; i++) {
		if (pthread_create(&t[i],NULL,func, (void*)fd)) {
			perror("pthread_creat");
			exit(-1);
		}
	}

	sched_yield();
	run = 0;
	for (i=0; i < NR_THREADS; i++)
		pthread_join(t[i], NULL);


	close (fd);
	exit(0);
}