title: Can't figure out what is wrong with this Strict Standards: Only variables should be passed by reference
body: <p>I get an error on the line where I bind values in the following function:</p>
  
  <pre><code>    function update_vote_logs($accid, $site_id){
      global $host_ip, $auth_db, $db_username, $db_password, $character_db, $world_db, $web_db;
      $con = connect($host_ip, $db_username, $db_password, $web_db);
      $exp = time() + (43200);
      $sql = "REPLACE INTO `vote_logs` VALUES (?,?,?,?)";
      if (check_if_voted($accid, $site_id) == 0 || check_if_voted($accid, $site_id) == 2){
          if ($stmt = $con-&gt;prepare($sql)) {
              $stmt-&gt;bind_param("iiii", $accid, $site_id, time(), $exp);
              $stmt-&gt;execute();
              $stmt-&gt;store_result();
          }
      }
      $stmt-&gt;close();
      $con-&gt;close();
  }
  </code></pre>
  
  <p>This is the line which causes the error:</p>
  
  <pre><code> $stmt-&gt;bind_param("iiii", $accid, $site_id, time(), $exp); 
  </code></pre>
  
  <p>I'm learning PHP and this is the first time I've seen this warning.</p>
  
  <p>Can anyone help me?</p>