<?php

class F{
    public function __construct(){
        if(method_exists($this, ‘son_fun1‘)){
            echo ‘son_fun1存在‘;
        }else{
            echo ‘son_fun1不存在‘;
        }
        if(method_exists($this,‘son_fun2‘)){
            echo ‘son_fun2存在‘;
        }else{
            echo ‘son_fun2不存在‘;
        }
    }
}
class S extends F{
    public function son_fun1(){
    }
}
$a = new S();

<?php
error_reporting(E_ALL);
function increment(&$var)
{
    $var++;
}

$a = 0;
call_user_func(‘increment‘, $a);
echo $a."\n";

// You can use this instead
call_user_func_array(‘increment‘, array(&$a));//要被传入回调函数的数组得是索引数组。
echo $a."\n";