title: How to get current timestamp in nanoseconds in linux using c
body: <p>I know we can use <code>clock_gettime(CLOCK_MONOTONIC)</code>.</p>
  
  <p>Question i try asking is that if i need the time in nanoseconds
  say from epoch, it would be a huge number.</p>
  
  <p>For example:</p>
  
  <ul>
  <li>Seconds since epoch is <code>13438461673</code> so <code>13438461673 * 1000000000</code></li>
  </ul>
  
  <p>How do i fit it inside a 64bit integer?</p>