Yaf_Application::getLastErrorMsg

<?php
function error_handler($errno, $errstr, $errfile, $errline) {
   var_dump(Yaf_Application::app()->getLastErrorMsg());
}

$config = array(                   
 "application" => array(
   "directory" => "/tmp/notexists",
     "dispatcher" => array(
       "throwException" => 0, //trigger error instead of throw exception when error occure
      ),
  ),
);

$app = new Yaf_Application($config);
$app->getDispatcher()->setErrorHandler("error_handler", E_RECOVERABLE_ERROR);
$app->run();
?>

The above example will output something similar to: