title: how does current->pid work for linux?
body: <p>Do I need to include a library? 
  Can anyone please elaborate in it?</p>
  
  <p>I know is used to get the process id of the current task where is being called from</p>
  
  <p>But I want to printk something with current->pid </p>
  
  <p><code>printk("My current process id/pid is %d\n", current-&gt;pid);</code></p>
  
  <p>...and is giving me an error</p>
  
  <p><code>error: dereferencing pointer to incomplete type</code></p>