php call_user_func的简介

<?php // 普通的回调函数function my_callback_function() {    echo 'hello world!';}// 回调方法class MyClass {    static function myCallbackMethod() {        echo 'Hello World!';    }}// Type 1: 简单的回调call_user_func('my_callback_function'); // Type 2: 静态类回调call_user_func(array('MyClass', 'myCallbackMethod')); // Type 3: 类方法回调$obj = new MyClass();call_user_func(array($obj, 'myCallbackMethod'));// Type 4: 调用类方法 (As of PHP 5.2.3)call_user_func('MyClass::myCallbackMethod');// Type 5: 相对静态类方法的调用(As of PHP 5.3.0)class A {    public static function who() {        echo "A\n";    }}class B extends A {    public static function who() {        echo "B\n";    }}call_user_func(array('B', 'parent::who')); // A?>