#include <stdio.h>
#include <stdlib.h>
#include <time.h>

#define NANOSEC    1000000000.0
#define MILLISEC   1000

int displaytimer=0;
static  struct timespec start;

void start_timer()
{
    printf("timer started...\n");
    clock_gettime(CLOCK_MONOTONIC, &start);
#   ifdef DEBUG_TIMER
    printf("sec=%d nsec=%d\n", start.tv_sec, start.tv_nsec);
#   endif
}

void set_timer(timer)
    struct timespec *timer;
{
    clock_gettime(CLOCK_MONOTONIC, timer);
#   ifdef DEBUG_TIMER
    printf("timer: sec=%d nsec=%d orig: sec=%ld nsec=%ld\n",
           timer->tv_sec, timer->tv_nsec, start.tv_sec, start.tv_nsec);
#   endif
}

double get_timer(timer)
    struct timespec timer;
{
    double diff;
    diff=(timer.tv_sec - start.tv_sec) + (timer.tv_nsec - start.tv_nsec) / NANOSEC;
#   ifdef DEBUG_TIMER
    printf("timer sec: %.5f\n", diff);
#   endif
    return diff;
}

#ifdef STANDALONE
int main(ac, av)
    int ac;
    char **av;
{
    int delay;
    struct timespec end, tsdelay;

    if (ac != 2) {
        fprintf(stderr, "usage: %s msecs\n", *av);
        exit (1);
    }
    delay=atoi(*(av+1));
    start_timer();
    tsdelay.tv_sec=delay/MILLISEC;
    tsdelay.tv_nsec=delay%MILLISEC;
    printf("delay %d=%ld:%ld\n", delay, tsdelay.tv_sec, tsdelay.tv_nsec);
    nanosleep(&tsdelay, NULL);
    set_timer(&end);
    printf("Time elapsed: %.5f seconds\n", get_timer(end));

    return 0;
}
#endif