<?php
// this makes ob_end_clean raise an error
ob_end_flush();

class ExceptionHandler {
    public function __invoke (Exception $e)
    {
        // this triggers the custom error handler
        ob_end_clean();
    }
}

// this must be a class, closure does not trigger segfault
set_exception_handler(new ExceptionHandler());

// exception must be thrown from error handler.
set_error_handler(function()
{
    $e = new Exception;
    $e->_trace = debug_backtrace();

    throw $e;
});

// trigger error handler
$a['waa'];
?>