title: pid for new thread
body: <p>I have a quick question about new thread created by pthread_create():</p>
  
  <p>When I print the pid (get from getpid()) of main thread and the child thread, they are the same while when I using htop linux utility to show pid, they are different. Can any one explain this to me?? Thanks!!</p>
  
  <pre><code>kai@kai-T420s:~/LPI$ ./pthr_create
  --------------------------------------
  main thread: pid: 4845, ppid: 3335
  child thread: pid: 4845, ppid: 3335
  </code></pre>
  
  <p>htop shows:
  <img src="https://i.stack.imgur.com/BN14L.png" alt="Screenshot of the htop application showing a list of processes."></p>