title: What does it mean when I can't "use method return value in write context"?
body: <p>When I use this statement <code>if(count($this-&gt;input-&gt;post('p_id') =0))</code>, I keep getting this error:</p>
  
  <pre><code>    Fatal error: Can't use method return value in write context in 
  C:\xampp\htdocs\CI\professional_ci\application\models\MProducts.php  on line 249
  </code></pre>
  
  <p>But when I use <code>if(count($this-&gt;input-&gt;post('p_id')))</code>, it works. What does it mean I can't use method return?</p>