TYPO3 v8 has reached its end-of-life March 31st, 2020 and is not maintained by the community anymore.

You can order Extended Long Term Support (ELTS) here: TYPO3 ELTS.

Extending the error and exception handling

If you want to register your own error or exception handler, simply include the class and insert its name into "productionExceptionHandler", "debugExceptionHandler" or "errorHandler":

$TYPO3_CONF_VARS['SYS']['errorHandler'] = 'myOwnErrorHandler';
$TYPO3_CONF_VARS['SYS']['debugExceptionHandler'] = 'myOwnDebugExceptionHandler';
$TYPO3_CONF_VARS['SYS']['productionExceptionHandler'] = 'myOwnProductionExceptionHandler';

An error or exception handler class must register an error (exception) handler in its constructor. Have a look at the files in EXT:core/Classes/Error/ to see how this should be done.

If you want to use the built-in error and exception handling but extend it with your own functionality, simply derive your class from the error and exception handling classes shipped with TYPO3 and register this class as error (exception) handler:

class tx_postExceptionsOnTwitter extends \TYPO3\CMS\Core\Error\DebugExceptionHandler {
    function echoExceptionWeb(Exception $exception) {
    function postExceptionsOnTwitter($exception) {
        // do it ;-)
$TYPO3_CONF_VARS['SYS']['debugExceptionHandler'] = 'tx_postExceptionsOnTwitter';
$TYPO3_CONF_VARS['SYS']['productionExceptionHandler'] = 'tx_postExceptionsOnTwitter';