输出数据的问题

<?php
require("/var/www/betacom/Comment.php");
$comment=new Comment();
$result=$comment->viewcontent();//viewcontent()函数返回执行查询语句的数组

echo "<table>\n";
echo "<tr>\n";
while($row=fetch_row($result))
{

echo '<td bgcolor="#00FF00">';
echo "$row[1]";
echo '</td>';

echo '<td bgcolor="#00FF00">';
echo "$row[2]";
echo '</td>';

echo '<td bgcolor="#00FF00">';
echo "$row[3]";
echo '</td>';
}
echo "</tr>\n";
echo "</table>\n";
?>

运行的时候错误提示如下：
Call to undefined function fetch_row() in /var/www/betacom/showlist.php on line 23