Struct Stderr

pub struct Stderr { /* private fields */ }

Available on crate feature std only.

A handle to the standard error stream of a process.

For more information, see the io::stderr 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.

Implementations

impl Stderr

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

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(())
}

Trait Implementations

impl AsFd for Stderr

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

Borrows the file descriptor.

impl AsRawFd for Stderr

fn as_raw_fd(&self) -> i32

Extracts the raw file descriptor.

impl Debug for Stderr

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

Formats the value using the given formatter.

impl IsTerminal for Stderr

fn is_terminal(&self) -> bool

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

impl Write for &Stderr

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

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

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

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)

Determines if this Writer has an efficient write_vectored implementation.

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

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

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

Attempts to write an entire buffer into this writer.

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

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

Attempts to write multiple buffers into this writer.

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

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, Error>

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

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

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)

Determines if this Writer has an efficient write_vectored implementation.

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

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

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

Attempts to write an entire buffer into this writer.

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

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

Attempts to write multiple buffers into this writer.

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

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 Stderr

impl UnwindSafe for Stderr

Layout

Note: Most layout information is completely unstable and may even differ between compilations. The only exception is types with certain repr(...) attributes. Please see the Rust Reference's “Type Layout” chapter for details on type layout guarantees.

Size: 8 bytes