Struct std::process::ChildStderr

pub struct ChildStderr { /* fields omitted */ }

A handle to a child process's stderr.

This struct is used in the stderr field on Child.

When an instance of ChildStderr is dropped, the ChildStderr's underlying file handle will be closed.

Trait Implementations

impl Read for ChildStderr

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

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

unsafe fn initializer(&self) -> Initializer

🔬 This is a nightly-only experimental API. (read_initializer #42788)

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

fn read_vectored(&mut self, bufs: &mut [IoVecMut]) -> Result<usize>

🔬 This is a nightly-only experimental API. (iovec #58452)

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

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

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

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

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

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

Read the exact number of bytes required to fill buf.

Important traits for &'_ mut I

impl<'_, I> Iterator for &'_ mut I where
    I: Iterator + ?Sized,  type Item = <I as Iterator>::Item;impl<'_, F> Future for &'_ mut F where
    F: Unpin + Future + ?Sized,  type Output = <F as Future>::Output;impl<R: Read + ?Sized, '_> Read for &'_ mut Rimpl<W: Write + ?Sized, '_> Write for &'_ mut W

fn by_ref(&mut self) -> &mut Self where
    Self: Sized, 

Creates a "by reference" adaptor for this instance of Read.

Important traits for Bytes<R>

impl<R: Read> Iterator for Bytes<R> type Item = Result<u8>;

fn bytes(self) -> Bytes<Self> where
    Self: Sized, 

Transforms this Read instance to an [Iterator] over its bytes.

Important traits for Chain<T, U>

impl<T: Read, U: Read> Read for Chain<T, U>

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

Creates an adaptor which will chain this stream with another.

Important traits for Take<T>

impl<T: Read> Read for Take<T>

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

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

impl AsRawFd for ChildStderr

fn as_raw_fd(&self) -> RawFd

This is supported on Unix only.

Extracts the raw file descriptor.

impl IntoRawFd for ChildStderr

fn into_raw_fd(self) -> RawFd

This is supported on Unix only.

Consumes this object, returning the raw underlying file descriptor.

impl AsRawHandle for ChildStderr

fn as_raw_handle(&self) -> RawHandle

This is supported on Windows only.

Extracts the raw handle, without taking any ownership.

impl IntoRawHandle for ChildStderr

fn into_raw_handle(self) -> RawHandle

This is supported on Windows only.

Consumes this object, returning the raw underlying handle.

impl Debug for ChildStderr

fn fmt(&self, f: &mut Formatter) -> Result

Formats the value using the given formatter.

impl From<ChildStderr> for Stdio

fn from(child: ChildStderr) -> Stdio

Converts a ChildStderr into a Stdio

Examples

use std::process::{Command, Stdio};

let reverse = Command::new("rev")
    .arg("non_existing_file.txt")
    .stderr(Stdio::piped())
    .spawn()
    .expect("failed reverse command");

let cat = Command::new("cat")
    .arg("-")
    .stdin(reverse.stderr.unwrap()) // Converted into a Stdio here
    .output()
    .expect("failed echo command");

assert_eq!(
    String::from_utf8_lossy(&cat.stdout),
    "rev: cannot open non_existing_file.txt: No such file or directory\n"
);