1--TEST-- 2Testing interface_exists() 3--FILE-- 4<?php 5 6interface foo { 7} 8 9var_dump(interface_exists('foo')); 10var_dump(interface_exists(1)); 11var_dump(interface_exists(NULL)); 12var_dump(interface_exists(new stdClass)); 13 14?> 15--EXPECTF-- 16bool(true) 17bool(false) 18bool(false) 19 20Warning: interface_exists() expects parameter 1 to be string, object given in %s on line %d 21NULL 22