Callback

Person.php

<?php
class Person {
    private $name;    
    private $age;    
    private $id;    

    function __construct( $name, $age ) {
        $this->name = $name;
        $this->age = $age;
    }

    function setId( $id ) {
        $this->id = $id;
    }
    
    function getId(){
        echo $this->id;    
    }
    
    function __clone() {
        $this->id = 0;
    }
}

$p = new Person("A",10); 
call_user_func( array( $p, 'setId' ), 20 );

$p->getId();

?>