如何使用`read_line()`检查EOF? [英] How to check for EOF with `read_line()`?

问题描述

给定下面的代码，我如何专门检查 EOF?或者更确切地说，我如何区分这里什么都没有"和它爆炸了"?

Given the code below, how can I specifically check for EOF? Or rather, how can I distinguish between "there's nothing here" and "it exploded"?

match io::stdin().read_line() {
    Ok(l) => print!("{}", l),
    Err(_) => do_something_else(),
}

推荐答案

来自 read_line 的文档:

From the documentation for read_line:

如果成功，此函数将返回读取的总字节数.

If successful, this function will return the total number of bytes read.

如果此函数返回Ok(0)，则流已达到EOF.

If this function returns Ok(0), the stream has reached EOF.

这意味着我们可以检查成功的零值:

This means we can check for a successful value of zero:

use std::io::{self, BufRead};

fn main() -> io::Result<()> {
    let mut empty: &[u8] = &[];
    let mut buffer = String::new();

    let bytes = empty.read_line(&mut buffer)?;
    if bytes == 0 {
        println!("EOF reached");
    }

    Ok(())
}

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