<?php
ini_set('error_reporting', E_ALL);
ini_set('display_errors', 0);
ini_set('log_errors', 1);
ini_set('error_log', 'php_error.log');

function myErrorHandler($errno, &$errstr, $errfile, $errline) {
  $exception = new ErrorException($errstr, $errno, 0, $errfile, $errline);
  $errstr .= ', '.$exception->__toString();
  return false; // continue normal error handler
}

set_error_handler('myErrorHandler');

function test(){
  test2('bar');
}
function test2(){
  echo tests.PHP_EOL; // Use of undefined constant tests
}
test('foo');