Struct std::io::Stderr

pub struct Stderr { /* fields omitted */ }

A handle to the standard error stream of a process.

For more information, see the io::stderr 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 write bytes that are not valid UTF-8 will return an error.

Implementations

impl Stderr

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

Locks this handle to the standard error 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 foo() -> io::Result<()> {
    let stderr = io::stderr();
    let mut handle = stderr.lock();

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

    Ok(())
}

pub fn into_locked(self) -> StderrLock<'static>

🔬 This is a nightly-only experimental API. (stdio_locked #86845)

Locks and consumes this handle to the standard error stream, returning a writable guard.

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

Examples

#![feature(stdio_locked)]
use std::io::{self, Write};

fn foo() -> io::Result<()> {
    let stderr = io::stderr();
    let mut handle = stderr.into_locked();

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

    Ok(())
}

Trait Implementations

impl AsFd for Stderr

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

🔬 This is a nightly-only experimental API. (io_safety #87074)

This is supported on Unix only.

Borrows the file descriptor.

impl AsHandle for Stderr

This is supported on Windows only.

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

🔬 This is a nightly-only experimental API. (io_safety #87074)

Borrows the handle.

impl AsRawFd for Stderr

fn as_raw_fd(&self) -> RawFd

This is supported on Unix only.

Extracts the raw file descriptor.

impl AsRawHandle for Stderr

This is supported on Windows only.

fn as_raw_handle(&self) -> RawHandle

Extracts the raw handle, without taking any ownership.

impl Debug for Stderr

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

Formats the value using the given formatter.

impl Write for Stderr

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

Write 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<()>

Flush 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 &Stderr

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

Write 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<()>

Flush 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.