Struct std::io::Stdin
pub struct Stdin { /* private fields */ }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 stdin = io::stdin(); // We get `Stdin` here.
stdin.read_line(&mut buffer)?;
Ok(())
}Implementations
impl Stdinpub fn lock(&self) -> StdinLock<'static> ⓘ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(())
}pub fn read_line(&self, buf: &mut String) -> Result<usize>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}"),
}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
pub fn lines(self) -> Lines<StdinLock<'static>> ⓘ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());
}Trait Implementations
impl AsFd for Stdinimpl AsHandle for StdinAvailable on Windows only.impl AsRawFd for Stdinimpl AsRawHandle for StdinAvailable on Windows only.impl Debug for Stdinfn fmt(&self, f: &mut Formatter<'_>) -> Result
Formats the value using the given formatter. Read more
impl IsTerminal for Stdinfn is_terminal(&self) -> bool
Returns
true if the descriptor/handle refers to a terminal/tty. Read more
impl Read for Stdinfn read(&mut self, buf: &mut [u8]) -> Result<usize>
Pull some bytes from this source into the specified buffer, returning how many bytes were read. Read more
fn read_buf(&mut self, buf: BorrowedCursor<'_>) -> Result<()>🔬This is a nightly-only experimental API. (
read_buf #78485)
Pull some bytes from this source into the specified buffer. Read more
fn read_vectored(&mut self, bufs: &mut [IoSliceMut<'_>]) -> Result<usize>
Like
read, except that it reads into a slice of buffers. Read more
fn is_read_vectored(&self) -> bool🔬This is a nightly-only experimental API. (
can_vector #69941)
fn read_to_end(&mut self, buf: &mut Vec<u8>) -> Result<usize>
Read all bytes until EOF in this source, placing them into
buf. Read more
fn read_to_string(&mut self, buf: &mut String) -> Result<usize>
Read all bytes until EOF in this source, appending them to
buf. Read more
fn read_exact(&mut self, buf: &mut [u8]) -> Result<()>
Read the exact number of bytes required to fill
buf. Read more
fn read_buf_exact(&mut self, cursor: BorrowedCursor<'_>) -> Result<()>🔬This is a nightly-only experimental API. (
read_buf #78485)
Read the exact number of bytes required to fill
cursor. Read more
fn by_ref(&mut self) -> &mut Self
where
Self: Sized,
Creates a “by reference” adaptor for this instance of
Read. Read more
fn bytes(self) -> Bytes<Self> ⓘ
where
Self: Sized,fn chain<R: Read>(self, next: R) -> Chain<Self, R> ⓘ
where
Self: Sized,
Creates an adapter which will chain this stream with another. Read more
fn take(self, limit: u64) -> Take<Self> ⓘ
where
Self: Sized,
Creates an adapter which will read at most
limit bytes from it. Read more
Auto Trait Implementations
impl RefUnwindSafe for Stdinimpl Send for Stdinimpl Sync for Stdinimpl Unpin for Stdinimpl UnwindSafe for StdinBlanket Implementations
impl<T> Any for T
where
T: 'static + ?Sized,impl<T> Borrow<T> for T
where
T: ?Sized,impl<T> BorrowMut<T> for T
where
T: ?Sized,impl<T> From<T> for Tfn from(t: T) -> TReturns the argument unchanged.
impl<T, U> Into<U> for T
where
U: From<T>,fn into(self) -> UCalls U::from(self).
That is, this conversion is whatever the implementation of From<T> for U chooses to do.
impl<T, U> TryFrom<U> for T
where
U: Into<T>,type Error = Infallible
The type returned in the event of a conversion error.
fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>
Performs the conversion.
impl<T, U> TryInto<U> for T
where
U: TryFrom<T>,type Error = <U as TryFrom<T>>::Error
The type returned in the event of a conversion error.
fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>
Performs the conversion.
© 2010 The Rust Project Developers
Licensed under the Apache License, Version 2.0 or the MIT license, at your option.
https://doc.rust-lang.org/std/io/struct.Stdin.html