PHPの関数の参照渡しと戻り方を詳しく解説（コード付き）

<?php
    $a = &#39;abc&#39;;
    $b = &$a;
    var_dump($a,$b);//均为&#39;abc&#39;
    $b = 123;
    var_dump($a,$b);//均为123

<?php
    function test(&$a){
        $a = $a + 100;
    }
    $b = 1;
    test($b);
    var_dump($b);//101

<?php
    function test(&$a){
        $a = $a + 10;
    }
    $b = 1;
    call_user_func_array(&#39;test&#39;,array(&$b));
    var_dump($b);//11

function &test()
{
    static $b=0;//申明一个静态变量
    $b=$b+1;
    echo $b;
    return $b;
}
$a=test();//这条语句会输出　$b的值　为１
$a=5;
$a=test();//这条语句会输出　$b的值　为2
$a=&test();//这条语句会输出　$b的值　为3
$a=5;
$a=test();//这条语句会输出　$b的值　为6

class talker{
private $data = 'Hi';
    public function &get(){
        return $this->data;
    }
    public function out(){
        echo $this->data;
    }
}
$aa = new talker();
$d = &$aa->get();
$aa->out();
$d = 'How';
$aa->out();
$d = 'Are';
$aa->out();
$d = 'You';
$aa->out(); 
//输出为HiHowAreYou