Struct Stdout 

pub struct Stdout {
    inner: &'static ReentrantLock<RefCell<LineWriter<StdoutRaw>>>,
}

A handle to the global standard output stream of the current process.

Each handle shares a global buffer of data to be written to the standard output stream. Access is also synchronized via a lock and explicit control over locking is available via the lock method.

By default, the handle is line-buffered when connected to a terminal, meaning it flushes automatically when a newline (\n) is encountered. For immediate output, you can manually call the flush method. When the handle goes out of scope, the buffer is automatically flushed.

Created by the io::stdout 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 write 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.

Fields

inner: &'static ReentrantLock<RefCell<LineWriter<StdoutRaw>>>

Implementations

impl Stdout

pub fn lock(&self) -> StdoutLock<'static>

Locks this handle to the standard output stream, returning a writable guard.

The lock is released when the returned lock goes out of scope. The returned guard also implements the Write trait for writing data.

Examples

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

fn main() -> io::Result<()> {
    let mut stdout = io::stdout().lock();

    stdout.write_all(b"hello world")?;

    Ok(())
}

Trait Implementations

impl AsFd for Stdout

Available on Unix or Hermit or Trusty or WASI or Motor OS only.

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

Borrows the file descriptor.

impl AsRawFd for Stdout

Available on Unix or Hermit or Trusty or WASI or Motor OS only.

fn as_raw_fd(&self) -> RawFd

Extracts the raw file descriptor.

impl Debug for Stdout

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

Formats the value using the given formatter.

impl From<Stdout> for Stdio

fn from(inherit: Stdout) -> Stdio

Redirect command stdout/stderr to our stdout

Examples

#![feature(exit_status_error)]
use std::io;
use std::process::Command;

let output = Command::new("whoami")
    .stdout(io::stdout())
    .output()?;
output.status.exit_ok()?;
assert!(output.stdout.is_empty());

impl From<Stdout> for Stdio

fn from(_: Stdout) -> Stdio

Converts to this type from the input type.

impl IsTerminal for Stdout

fn is_terminal(&self) -> bool

Returns true if the descriptor/handle refers to a terminal/tty.

impl StdioExt for Stdout

Available on non-Hermit and (Unix) and not ((WebAssembly and non-WASI, or Fortanix and SGX)) only.

fn set_fd<T: Into<OwnedFd>>(&mut self, fd: T) -> Result<()>

🔬This is a nightly-only experimental API. (stdio_swap #150667)

Redirects the stdio file descriptor to point to the file description underpinning fd.

fn take_fd(&mut self) -> Result<OwnedFd>

🔬This is a nightly-only experimental API. (stdio_swap #150667)

Redirects the stdio file descriptor to the null device (/dev/null) and returns a new OwnedFd backed by the previous file description.

fn replace_fd<T: Into<OwnedFd>>(&mut self, replace_with: T) -> Result<OwnedFd>

🔬This is a nightly-only experimental API. (stdio_swap #150667)

Redirects the stdio file descriptor and returns a new OwnedFd backed by the previous file description.

impl Write for &Stdout

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

Writes a buffer into this writer, returning how many bytes were written.

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

Like write, except that it writes from a slice of buffers.

fn is_write_vectored(&self) -> bool

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

Determines if this Writer has an efficient write_vectored implementation.

fn flush(&mut self) -> Result<()>

Flushes this output stream, ensuring that all intermediately buffered contents reach their destination.

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

Attempts to write an entire buffer into this writer.

fn write_all_vectored(&mut self, bufs: &mut [IoSlice<'_>]) -> Result<()>

🔬This is a nightly-only experimental API. (write_all_vectored #70436)

Attempts to write multiple buffers into this writer.

fn write_fmt(&mut self, args: Arguments<'_>) -> Result<()>

Writes a formatted string into this writer, returning any error encountered.

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

where Self: Sized,

Creates a “by reference” adapter for this instance of Write.

impl Write for Stdout

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

Writes a buffer into this writer, returning how many bytes were written.

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

Like write, except that it writes from a slice of buffers.

fn is_write_vectored(&self) -> bool

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

Determines if this Writer has an efficient write_vectored implementation.

fn flush(&mut self) -> Result<()>

Flushes this output stream, ensuring that all intermediately buffered contents reach their destination.

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

Attempts to write an entire buffer into this writer.

fn write_all_vectored(&mut self, bufs: &mut [IoSlice<'_>]) -> Result<()>

🔬This is a nightly-only experimental API. (write_all_vectored #70436)

Attempts to write multiple buffers into this writer.

fn write_fmt(&mut self, args: Arguments<'_>) -> Result<()>

Writes a formatted string into this writer, returning any error encountered.

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

where Self: Sized,

Creates a “by reference” adapter for this instance of Write.

impl RefUnwindSafe for Stdout

impl Sealed for Stdout

impl UnwindSafe for Stdout