title: Which file should I pass as pathname argument of ftok()
body: <p>It is mentioned in ftok() manual </p>
  
  <pre><code>key_t ftok(const char *pathname, int proj_id);
  </code></pre>
  
  <p>The  ftok()  function  uses  the identity of the file named by the given pathname <strong>(which must refer to an existing, accessible file)</strong> ...</p>
  
  <p>I am confused about <code>const char *pathname</code>.</p>
  
  <p>What would be the best practice for it? 
  On my current system I can pass <code>"/home/Andrew/anyfile"</code> but it is not possible that other systems, on which my program has to work, will have this file.</p>
  
  <p>How about I use <code>"/etc/hosts/"</code> or <code>"/etc/inittab"</code> because I am sure all such systems will have these two files? Is it a good idea? Can it cause any problem?</p>
  
  <p>I do not want to ask user to enter filename at the time of execution or pass file name as command line argument.</p>
  
  <p>Is there any other different and better way to decide <code>pathname</code>? <br/>
  Which way is the best and most reliable one?</p>
  
  <p>Thanks for your time.</p>