# 文件I/O

这里的介绍文件操作，

* 一种是基于文件描述符的I/O操作。(由Linux内核操作管理文件)
* 一种是基于流的I/O操作。（流I/O是由C语言的标准函数库提供的，因此也称为标准I/O）

如图各自所在的层

![](/files/-LfnTJH3GU6I2ndJLZwu)

C语言的标准库，在用户空间，基于流的标准I/O：流和FILE对象。

linux底层系统调用，在内核空间，基于文件描述符的底层系统调用I/O。


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://xiaoxiami.gitbook.io/linux-server/wen-jian-cao-zuo.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.