1--TEST-- 2Call to date function from a method and call to date method from call_user_func 3--INI-- 4date.timezone=UTC 5--FILE-- 6<?php 7 8class Date { 9 public function __construct($in) { 10 $this->date = date_create($in); 11 } 12 13 public function getYear1() { 14 return date_format($this->date, 'Y'); 15 } 16 17 public function getYear2() { 18 return call_user_func([$this->date, 'format'], 'Y'); 19 } 20} 21 22$d = new Date('NOW'); 23var_dump($d->getYear1()); 24var_dump($d->getYear2()); 25 26?> 27--EXPECTF-- 28string(4) "%d" 29string(4) "%d" 30