Struct std::io::Stdin

1.0.0 · source · []
pub struct Stdin { /* private fields */ }
Expand description

A handle to the standard input stream of a process.

Each handle is a shared reference to a global buffer of input data to this process. A handle can be lock’d to gain full access to BufRead methods (e.g., .lines()). Reads to this handle are otherwise locked with respect to other reads.

This handle implements the Read trait, but beware that concurrent reads of Stdin must be executed with care.

Created by the io::stdin method.

Note: Windows Portability Considerations

When operating in a console, the Windows implementation of this stream does not support non-UTF-8 byte sequences. Attempting to read bytes that are not valid UTF-8 will return an error.

In a process with a detached console, such as one using #![windows_subsystem = "windows"], or in a child process spawned from such a process, the contained handle will be null. In such cases, the standard library’s Read and Write will do nothing and silently succeed. All other I/O operations, via the standard library or via raw Windows API calls, will fail.

Examples

use std::io;

fn main() -> io::Result<()> {
    let mut buffer = String::new();
    let mut stdin = io::stdin(); // We get `Stdin` here.
    stdin.read_line(&mut buffer)?;
    Ok(())
}
Run

Implementations

Locks this handle to the standard input stream, returning a readable guard.

The lock is released when the returned lock goes out of scope. The returned guard also implements the Read and BufRead traits for accessing the underlying data.

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

fn main() -> io::Result<()> {
    let mut buffer = String::new();
    let stdin = io::stdin();
    let mut handle = stdin.lock();

    handle.read_line(&mut buffer)?;
    Ok(())
}
Run

Locks this handle and reads a line of input, appending it to the specified buffer.

For detailed semantics of this method, see the documentation on BufRead::read_line.

Examples
use std::io;

let mut input = String::new();
match io::stdin().read_line(&mut input) {
    Ok(n) => {
        println!("{n} bytes read");
        println!("{input}");
    }
    Err(error) => println!("error: {error}"),
}
Run

You can run the example one of two ways:

  • Pipe some text to it, e.g., printf foo | path/to/executable
  • Give it text interactively by running the executable directly, in which case it will wait for the Enter key to be pressed before continuing

Consumes this handle and returns an iterator over input lines.

For detailed semantics of this method, see the documentation on BufRead::lines.

Examples
use std::io;

let lines = io::stdin().lines();
for line in lines {
    println!("got a line: {}", line.unwrap());
}
Run

Trait Implementations

🔬 This is a nightly-only experimental API. (io_safety #87074)
This is supported on Unix only.

Borrows the file descriptor. Read more

🔬 This is a nightly-only experimental API. (io_safety #87074)

Borrows the handle. Read more

This is supported on Unix only.

Extracts the raw file descriptor. Read more

Extracts the raw handle. Read more

Formats the value using the given formatter. Read more

Pull some bytes from this source into the specified buffer, returning how many bytes were read. Read more

Like read, except that it reads into a slice of buffers. Read more

🔬 This is a nightly-only experimental API. (can_vector #69941)

Determines if this Reader has an efficient read_vectored implementation. Read more

Read all bytes until EOF in this source, placing them into buf. Read more

Read all bytes until EOF in this source, appending them to buf. Read more

Read the exact number of bytes required to fill buf. Read more

🔬 This is a nightly-only experimental API. (read_buf #78485)

Pull some bytes from this source into the specified buffer. Read more

🔬 This is a nightly-only experimental API. (read_buf #78485)

Read the exact number of bytes required to fill buf. Read more

Creates a “by reference” adaptor for this instance of Read. Read more

Transforms this Read instance to an Iterator over its bytes. Read more

Creates an adapter which will chain this stream with another. Read more

Creates an adapter which will read at most limit bytes from it. Read more

Auto Trait Implementations

Blanket Implementations

Gets the TypeId of self. Read more

Immutably borrows from an owned value. Read more

Mutably borrows from an owned value. Read more

Returns the argument unchanged.

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

The type returned in the event of a conversion error.

Performs the conversion.

The type returned in the event of a conversion error.

Performs the conversion.