<slide title="PEAR::isError">
 <list fontsize="4em">
  <bullet>PEAR::isError() Implementation</bullet>
 </list>
 <example type="php" fontsize="1.5em">
  <text><![CDATA[<?php
function isError($data) {
    return (bool)(is_object($data) &&
                  (get_class($data) == 'pear_error' ||
                   is_subclass_of($data, 'pear_error')));
}
?>]]></text></example>
 <list fontsize="4em">
  <bullet>PEAR_Error may be subclassed</bullet>
 </list>
</slide>    
