Rust input/output: Difference between revisions
From wikinotes
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manual buffered read | manual buffered read | ||
<syntaxhighlight lang="rust"> | <syntaxhighlight lang="rust"> | ||
extern crate atty; | |||
use std::io::Read; | use std::io::Read; | ||
use std::str; | use std::str; |
Latest revision as of 08:34, 9 February 2023
Documentation
std::fs
https://doc.rust-lang.org/std/fs/index.html
Stdin, Stdout, Stderr
Stdout/Stderr
println!("out"); // write to stdout eprintln!("err"); // write to stderrStdin
NOTE:
rust nightly has a std::io::IsTerminal that checks if the stream is a pipe or a tty.
but besides this there is no builtin way to verify this.
you can do it manually with rust libc, but the most portable way is to use rust atty.read from stdin
extern crate atty; use std::io; use std::io::BufRead; /// read big files fn buffered_read_all_stdin() { // don't read unless stdin is a pipe if atty::is(atty::Stream::Stdin) { return } let stdin = io::stdin(); let handle = stdin.lock(); let lines: Vec<String> = handle .lines() .map(|res| res.unwrap_or_default()) .collect(); print!("START\n{}\nFINISH\n", lines.join("\n")); }manual buffered read
extern crate atty; use std::io::Read; use std::str; /// like `tail -f` fn manually_buffered_read_stdin() { // don't read unless stdin is a pipe if atty::is(atty::Stream::Stdin) { return } let mut buffer: [u8; 1024] = [0; 1024]; let stdin = io::stdin(); let mut handle = stdin.lock(); loop { let bytes_read = handle .read(&mut buffer[..]) .unwrap_or(0); // reached EOF if bytes_read == 0 { break; } print!("{}", str::from_utf8(&buffer).unwrap()); } }
User Input
let name = String::new(); io::stdin().read_line(&mut name);