usleep() to calculate elapsed time behaves weird

Question

I am calculating time elapsed in milli seconds for each successive call to handler function using the code below. When i use usleep(1000) i.e. 1 ms time difference between each

Answer 1

Remember that the tv_usec field of the timeval structure never goes to (or over) one million, instead the number of seconds is increased.

You have to use the tv_sec field as well in your calculation.