In fact, when Facebook first debuted, random aside, ID they used I believe an int to represent your profile IDs.

在Facebook创立之初，我猜他们使用int来表示配置文件。

哈佛公开课 - 计算机科学课程节选

It's instead outside of them and, by convention, at the top of the file so that I can access it anywhere, whether or not this is a good thing, remains to be seen.

它在函数的外面，按照惯例，在文件的顶端，所以我可以在任何地方使用它,不管这是不是好事情，拭目以待。

哈佛公开课 - 计算机科学课程节选