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PHP引述陷阱

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Release： 2016-06-13 13:14:12

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PHP引用陷阱
1. $a = '333';
    $c = &$a;
    $d = '888';
    $c = &$d;
    echo $c;
    echo $a;

2. $a = '333';
    $c = &$a;
    $d = '888';
    $c = $d;
    echo $c;
    echo $a;

其中第四行$c = $d和$c = &$d,导致的结果完全不一样.
$c = $d,因为$c是$a的一个引用,所以$c和$a的值都会变成888,
但是$c = &$d,是$c变成了$d的引用了,和$a已经没有关系了,所以此时$a的值还是333.
注意,引用只是一个别名而已,并不是指针.
其实类似于Unix的硬连接.
http://www.php.net/manual/zh/language.references.whatare.php

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