StdinLock

StdinLock is a locked, borrowing handle to the standard input provided by Rust’s standard library. It is produced by calling the lock method on a Stdin handle (for example, std::io::stdin().lock()) and represents exclusive access to standard input for the duration of the lock. The type is std::io::StdinLock<'a>, where 'a is the lifetime of the borrowed Stdin.

StdinLock implements the Read and BufRead traits, enabling both byte-wise and line-oriented input operations. This includes methods such as read, read_line, read_to_string, and the lines() iterator, as well as the lower-level BufRead methods like fill_buf and consume. Because it implements BufRead, it provides buffered access to input without requiring repeated system calls for each read.

The lock is released automatically when the StdinLock value goes out of scope (or is dropped), returning stdin to an unlocked state. This mechanism prevents data races when multiple parts of a program might attempt to read from standard input concurrently and ensures that a single, consistent stream is observed during the lock’s lifetime.

Usage typically involves obtaining a lock once and reusing it for subsequent reads within the scope. For example:

let stdin = std::io::stdin();

let mut lock = stdin.lock();

let mut line = String::new();

lock.read_line(&mut line).unwrap();

StdinLock is a lightweight, ephemeral guard around the global standard input. It is designed for simplicity and safety in single-process programs, and it can be wrapped or used directly alongside other standard I/O utilities in Rust. See also: Stdin, Read, BufRead, StdinLock and other lock types like StdoutLock.