在PHP中使用xor进行变量交换是否安全

Question

Is it safe to use this kind of variable swapping in php ?

$a^=$b^=$a^=$b;

Answer 1

No, because the variables may not be types that can be XORd the way you expect. The PHP idiom for swapping two variables (of any scalar type) in one line is:

list($a, $b) = array($b, $a);