/* should gives effective times of a nanosleep() */

#include <stdio.h>
#include <sys/time.h>
#include <time.h>

#define USEC_PER_SEC	1000000
#define NSEC_PER_SEC	1000000000L

#define timerdiff(a,b) ((double)((a)->tv_sec - (b)->tv_sec) + \
                         (double)((a)->tv_usec - (b)->tv_usec)/USEC_PER_SEC)

main()
{
	struct timeval pre_time, post_time;
	struct timespec req;
	double diff;
	int i;
	
	req.tv_sec = 0;
	req.tv_nsec = 10;
	for (i=0; i<15; i++){
		req.tv_nsec *= 10;
		if (req.tv_nsec >= NSEC_PER_SEC) {
			req.tv_nsec = 100;
			req.tv_sec++;
		}
		gettimeofday(&pre_time, NULL);
		nanosleep(&req, NULL);
		gettimeofday(&post_time, NULL);

		diff = timerdiff(&post_time, &pre_time);
		printf("%12.9f\t %12.9f\n", (double)req.tv_sec + ((double)req.tv_nsec/NSEC_PER_SEC), diff);
	}


}