Struct snarkvm_utilities::io::Stdin

pub struct Stdin { /* fields omitted */ }

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 Consideration

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.

Examples

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

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

Implementations

impl Stdin

pub fn lock(&self) -> StdinLock<'_>

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, Read};

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

    handle.read_to_string(&mut buffer)?;
    Ok(())
}

pub fn read_line(&self, buf: &mut String) -> Result<usize, Error>

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!("{} bytes read", n);
        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

Trait Implementations

impl AsRawFd for Stdin

pub fn as_raw_fd(&self) -> i32

Extracts the raw file descriptor.

impl Debug for Stdin

pub fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.

impl Read for Stdin

pub fn read(&mut self, buf: &mut [u8]) -> Result<usize, Error>

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

pub fn read_vectored(
    &mut self,
    bufs: &mut [IoSliceMut<'_>]
) -> Result<usize, Error>

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

pub fn is_read_vectored(&self) -> bool

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

Determines if this Reader has an efficient read_vectored implementation.

pub unsafe fn initializer(&self) -> Initializer

🔬 This is a nightly-only experimental API. (read_initializer)

Determines if this Reader can work with buffers of uninitialized memory.

pub fn read_to_end(&mut self, buf: &mut Vec<u8, Global>) -> Result<usize, Error>

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

pub fn read_to_string(&mut self, buf: &mut String) -> Result<usize, Error>

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

pub fn read_exact(&mut self, buf: &mut [u8]) -> Result<(), Error>

Read the exact number of bytes required to fill buf.

fn by_ref(&mut self) -> &mut Self

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

fn bytes(self) -> Bytes<Self>

Transforms this Read instance to an Iterator over its bytes.

fn chain<R>(self, next: R) -> Chain<Self, R> where
    R: Read, 

Creates an adaptor which will chain this stream with another.

fn take(self, limit: u64) -> Take<Self>

Creates an adaptor which will read at most limit bytes from it.