文件描述符是什么？

Question

文件描述符是什么？

在nodejs的文档中看到的，百度了一下还是不明白，请大佬帮解释一下。

When file is a file descriptor, the behavior is similar to calling fs.write() directly (which is recommended). See the notes below on using a file descriptor.

来源：https://nodejs.org/api/fs.htm...

Answer 1

简单的讲，就是一个唯一 ID，通过这个 ID，可以访问该文件，读写该文件

Answer 2

nodejs file descriptor

On POSIX systems, for every process, the kernel maintains a table of currently open files and resources. Each open file is assigned a simple numeric identifier called a file descriptor. At the system-level, all file system operations use these file descriptors to identify and track each specific file. Windows systems use a different but conceptually similar mechanism for tracking resources. To simplify things for users, Node.js abstracts away the specific differences between operating systems and assigns all open files a numeric file descriptor.

Answer 3

文件描述符（file descriptor）在形式上是一个非负整数。实际上，它是一个索引值，每一个文件描述符会与一个打开文件相对应。