clocktest.c

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

static long long ts_usecs(struct timespec t) {
  return (t.tv_sec * 1000000000 + t.tv_nsec);
}

int main() {
  struct timespec t0, t1;
  for (;;) {
    clock_gettime(CLOCK_MONOTONIC, &t0);
    clock_gettime(CLOCK_MONOTONIC, &t1);
    long long us0 = ts_usecs(t0);
    long long us1 = ts_usecs(t1);
    long long delta = llabs(us0 - us1);
    printf("%lld %lld %lld\n", us0, us1, delta);
  }
}

clocktest.py

from time import clock_gettime, CLOCK_MONOTONIC

while True:
    t0 = clock_gettime(CLOCK_MONOTONIC) * 1000000000
    t1 = clock_gettime(CLOCK_MONOTONIC) * 1000000000
    print('%d %d %d' % (t0, t1, abs(t1 - t0)))