title: left-hand operand of comma expression has no effect
body: <pre><code>for (count = index, packet_no = 0; 
       count &lt; TOTAL_OBJ, packet_no &lt; TOTAL_PKT; 
       count++, packet_no++)
  </code></pre>
  
  <p><code>=&gt;</code> left-hand operand of comma expression has no effect.</p>
  
  <p>I find the above code is correct and could not understand why this error comes.</p>