Struct async_std::io::Stderr

pub struct Stderr(_);

A handle to the standard error of the current process.

This writer is created by the stderr function. See its documentation for more.

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.

Methods

impl Stderr

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

This is supported on unstable only.

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 async_std::io;
use async_std::prelude::*;

let stderr = io::stderr();
let mut handle = stderr.lock().await;

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

Trait Implementations

impl Write for Stderr

fn poll_write(
    self: Pin<&mut Self>,
    cx: &mut Context,
    buf: &[u8]
) -> Poll<Result<usize>>

Attempt to write bytes from buf into the object.

fn poll_flush(self: Pin<&mut Self>, cx: &mut Context) -> Poll<Result<()>>

Attempt to flush the object, ensuring that any buffered data reach their destination.

fn poll_close(self: Pin<&mut Self>, cx: &mut Context) -> Poll<Result<()>>

Attempt to close the object.

fn poll_write_vectored(
    self: Pin<&mut Self>,
    cx: &mut Context,
    bufs: &[IoSlice]
) -> Poll<Result<usize>>

Attempt to write bytes from bufs into the object using vectored IO operations.

fn write<'a>(&'a mut self, buf: &'a [u8]) -> ImplFuture<Result<usize>> where
    Self: Unpin, 

Writes some bytes into the byte stream.

fn flush(&mut self) -> ImplFuture<Result<()>> where
    Self: Unpin, 

Flushes the stream to ensure that all buffered contents reach their destination.

fn write_vectored<'a>(
    &'a mut self,
    bufs: &'a [IoSlice<'a>]
) -> ImplFuture<Result<usize>> where
    Self: Unpin, 

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

fn write_all<'a>(&'a mut self, buf: &'a [u8]) -> ImplFuture<Result<()>> where
    Self: Unpin, 

Writes an entire buffer into the byte stream.

fn write_fmt<'a>(&'a mut self, fmt: Arguments) -> ImplFuture<Result<()>> where
    Self: Unpin, 

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

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

fn as_raw_handle(&self) -> RawHandle

This is supported on Windows only.

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.