Struct std::process::ChildStdout

pub struct ChildStdout {
    inner: AnonPipe,
}

A handle to a child process’s standard output (stdout).

This struct is used in the stdout field on Child.

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

Fields

inner: AnonPipe

Trait Implementations

impl AsFd for ChildStdout

Available on Unix only.

fn as_fd(&self) -> BorrowedFd<'_>

Borrows the file descriptor.

impl AsHandle for ChildStdout

Available on Windows only.

fn as_handle(&self) -> BorrowedHandle<'_>

Borrows the handle.

impl AsRawFd for ChildStdout

Available on Unix only.

fn as_raw_fd(&self) -> RawFd

Extracts the raw file descriptor.

impl AsRawHandle for ChildStdout

Available on Windows only.

fn as_raw_handle(&self) -> RawHandle

Extracts the raw handle.

impl CopyRead for ChildStdout

fn properties(&self) -> CopyParams

Extracts the file descriptor and hints/metadata, delegating through wrappers if necessary.

fn drain_to<W: Write>(&mut self, _writer: &mut W, _limit: u64) -> Result<u64>

Implementations that contain buffers (i.e. BufReader) must transfer data from their internal buffers into writer until either the buffers are emptied or limit bytes have been transferred, whichever occurs sooner. If nested buffers are present the outer buffers must be drained first.

fn taken(&mut self, _bytes: u64)

Updates Take wrappers to remove the number of bytes copied.

fn min_limit(&self) -> u64

The minimum of the limit of all Take<_> wrappers, u64::MAX otherwise. This method does not account for data BufReader buffers and would underreport the limit of a Take<BufReader<Take<_>>> type. Thus its result is only valid after draining the buffers via drain_to.

impl Debug for ChildStdout

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

Formats the value using the given formatter.

impl From<ChildStdout> for OwnedFd

Available on Unix only.

fn from(child_stdout: ChildStdout) -> OwnedFd

Converts to this type from the input type.

impl From<ChildStdout> for OwnedHandle

Available on Windows only.

fn from(child_stdout: ChildStdout) -> OwnedHandle

Converts to this type from the input type.

impl From<ChildStdout> for Stdio

fn from(child: ChildStdout) -> Stdio

Converts a ChildStdout into a Stdio.

Examples

ChildStdout will be converted to Stdio using Stdio::from under the hood.

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

let hello = Command::new("echo")
    .arg("Hello, world!")
    .stdout(Stdio::piped())
    .spawn()
    .expect("failed echo command");

let reverse = Command::new("rev")
    .stdin(hello.stdout.unwrap())  // Converted into a Stdio here
    .output()
    .expect("failed reverse command");

assert_eq!(reverse.stdout, b"!dlrow ,olleH\n");

impl IntoRawFd for ChildStdout

Available on Unix only.

fn into_raw_fd(self) -> RawFd

Consumes this object, returning the raw underlying file descriptor.

impl IntoRawHandle for ChildStdout

Available on Windows only.

fn into_raw_handle(self) -> RawHandle

Consumes this object, returning the raw underlying handle.

impl Read for ChildStdout

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.

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.

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

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

fn is_read_vectored(&self) -> bool

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

Determines if this Reader has an efficient read_vectored implementation.

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.

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.

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

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

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

Transforms this Read instance to an Iterator over its bytes.

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

Creates an adapter which will chain this stream with another.

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

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