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

int
main(int argc, char **argv)
{
    struct timeval time;
    struct timeval delay;
    int hh, mm, ss;
    int dsec;

    delay.tv_sec = 0;
    gettimeofday(&time, NULL);
    while (1) {
	/* Compute delay to next 0.1 second point */
	delay.tv_usec = 100000L - (time.tv_usec % 100000L);
	if (delay.tv_usec > 5000) {
	    /* Wait until 5ms before then */
	    delay.tv_usec -= 5000;
	    select(0, NULL, NULL, NULL, &delay);
	}
	gettimeofday(&time, NULL);
	ss = (time.tv_sec % 86400);	/* discard days */
	hh = ss /  3600;
	mm = (ss - hh*3600) / 60;
	ss %= 60;
	printf("\r%02d:%02d:%02d.%02d",
			hh, mm, ss, (time.tv_usec + 500) / 10000);
	fflush(stdout);
    }
}