扩展类是否继承静态var值(PHP)? [英] do extended classes inherit static var values (PHP)?

问题描述

如果我有一个包含静态var的基类，则设置此静态var，然后再扩展该基类的类，扩展后的类将保留我已经在其中设置的静态var的值.基类?

If I have a base class that contains a static var, I then set this static var, and then have a class that extends the base class, will the extended class retain the value of the static var that I have already set in the base class?

推荐答案

是的，尽管它们是不同的变量，但两个类中的静态变量都在同一引用集中.

Yes, although they're different variables, the static variables in both classes are in the same reference set.

但是，您可以通过使用引用分配(=&)或在扩展类中重新声明它来破坏此引用集:

You can break this reference set though, by using reference assignment (=&) or by redeclaring it in the extended class:

class base {
    public static $var;
}
class extended extends base {}

extended::$var = 8; // base::$var == 8
$t = 6;
extended::$var =& $t; // base::$var == 8; extended::$var == 6

class base {
    public static $var;
}
class extended extends base {
    public static $var;
}

extended::$var = 8; // base::$var == null; extended::$var == 8

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