是PHP Closure对象有资格进行垃圾回收 [英] Are PHP Closure Objects eligible for garbage collection

问题描述

我想知道是否有人知道PHP的匿名函数是否有资格进行垃圾收集？

I was wondering if anyone knows if PHP's anonymous functions are eligible for garbage collection?

我知道用 create_function 创建的函数不是垃圾回收，但是我没有找到任何引用关于用 function（）{} 语法（内部表示为Closure对象）创建的。

I know that functions created with create_function are not garbage collected but I haven't been able to find any reference about ones created with the function(){} syntax (internally represented as a Closure object).

推荐答案

PHP的垃圾回收器不区分事物类型 - 如果它至少有一个引用， 。

PHP's garbage collector does not discriminate between types of "things" - if it has at least one reference somewhere, it is kept. The moment this does not apply, the resource is garbage-collected.

这是不与使用 create_function相同。 ，因为除了引用它之外，PHP还在全局作用域中引用create_function引用。一个闭包（一个Closure对象，如果你喜欢，因为这是他们是！）只存在于它创建的范围+所有传递给它的。

This is not the same as using create_function, as PHP throws the create_function reference in the global scope in addition to referencing it. A closure (a Closure object, if you prefer, as this is what they are!) only exists in the scope it was created in + all the ones you pass it to.

如果你想说服自己，运行这个小代码：

If you want to convince yourself of it, run this little piece of code:

<?php
$r = memory_get_usage();
for ($i = 0; $i < 100; $i++) {
    $k = function() {echo "boo"; };
    if (memory_get_usage() > $r) {
            echo "Different memory count. Off by: ".(memory_get_usage() -$r);
    }
    $r = memory_get_usage();
}

用create_function替换 $ k 赋值，你会得到100。

You will get exactly one echo. Replace the $k assignment with create_function, and you'll get 100.

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