kernel/lib/Debug.php
public static function activateException(int $iLevel)
    {
        if (self::$_bFirstActivation === true) {

            self::_setFileNameInErrorFile();
            self::$_bFirstActivation = false;
        }

        self::_initLogFile();
        self::$_bActivateException = true;

        set_exception_handler(function ($oException)
        {
            $aContext = array('file' => $oException->getFile(), 'line' => $oException->getLine());
            self::getInstance()->critical($oException->getMessage(), $aContext);
        });
    }
public static function activateException(int $iLevel)
    {
        if (self::$_bFirstActivation === true) {

            self::_setFileNameInErrorFile();
            self::$_bFirstActivation = false;
        }

        self::_initLogFile();
        self::$_bActivateException = true;

        set_exception_handler(function ($oException)
        {
            $aContext = array('file' => $oException->getFile(), 'line' => $oException->getLine());
            self::getInstance()->critical($oException->getMessage(), $aContext);
        });
    }
activate Exception

@access public
@param  int $iLevel level of error
@return void