1--TEST-- 2Implicit initialisation when passing by reference 3--FILE-- 4<?php 5function passbyVal($val) { 6 echo "\nInside passbyVal call:\n"; 7 var_dump($val); 8} 9 10function passbyRef(&$ref) { 11 echo "\nInside passbyRef call:\n"; 12 var_dump($ref); 13} 14 15echo "\nPassing undefined by value\n"; 16passbyVal($undef1[0]); 17echo "\nAfter call\n"; 18var_dump($undef1); 19 20echo "\nPassing undefined by reference\n"; 21passbyRef($undef2[0]); 22echo "\nAfter call\n"; 23var_dump($undef2) 24?> 25--EXPECTF-- 26 27Passing undefined by value 28 29Notice: Undefined variable: undef1 in %s on line 13 30 31Inside passbyVal call: 32NULL 33 34After call 35 36Notice: Undefined variable: undef1 in %s on line 15 37NULL 38 39Passing undefined by reference 40 41Inside passbyRef call: 42NULL 43 44After call 45array(1) { 46 [0]=> 47 NULL 48} 49