title: Whats is purpose ftok in Message queues
body: <p>I have started reading message queues one of the IPC mechanism on Linux .But at very first step I have some very basic questions.</p>
  
  <ol>
  <li><p>Use of <code>ftok()</code> to generate unique ID (key) and what is unique ID which is to be generated.</p></li>
  <li><p>Can't we use simple a number to get our keys rather than using <code>ftok()</code>?</p></li>
  <li><p>What is the purpose of the argument <code>key</code> in the <code>msget</code> function?</p>
  
  <pre><code>#include "sys/msg.h"
  key = ftok("/home/beej/somefile", 'b');
  msqid = msgget(key, 0666 | IPC_CREAT);
  </code></pre></li>
  <li><p>What is the difference between <code>msqid</code> and <code>key</code>?</p></li>
  </ol>