title: PHP is_int is not performing as expected
body: <p>I have a page (index.php) that takes a <code>GET</code> variable from the URL and checks it for security purposes.  This <code>GET</code> variable should only be an integer.  I am using the following code to check this, but in all instances, integer or not, I get the index.php page.  The header never appears.  After this code, the rest of the page appears starting with the <code>html</code> tag.</p>
  
  <p>PHP:</p>
  
  <pre><code>&lt;?php ob_start(); session_start();
  $q=trim($_GET['q']);
  if (!is_numeric($q)){
  header("HTTP/1.0 404 Not Found");
  }
  ?&gt;
  </code></pre>