Trait AsFd 

pub trait AsFd {
    // Required method
    fn as_fd(&self) -> BorrowedFd<'_>;
}

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

A trait to borrow the file descriptor from an underlying object.

This is only available on unix platforms and must be imported in order to call the method. Windows platforms have a corresponding AsHandle and AsSocket set of traits.

Required Methods

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

Borrows the file descriptor.

Example

use std::fs::File;

let mut f = File::open("foo.txt")?;
let borrowed_fd: BorrowedFd<'_> = f.as_fd();

Dyn Compatibility

This trait is dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety".

Implementors

impl AsFd for Dir

impl AsFd for std::fs::File

Available on non-Trusty only.

impl AsFd for PipeReader

Available on non-Trusty only.

impl AsFd for PipeWriter

Available on non-Trusty only.

impl AsFd for Stderr

impl AsFd for Stdin

impl AsFd for Stdout

impl AsFd for TcpListener

Available on non-Trusty only.

impl AsFd for TcpStream

Available on non-Trusty only.

impl AsFd for UdpSocket

Available on non-Trusty only.

impl AsFd for ChildStderr

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

impl AsFd for ChildStdin

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

impl AsFd for ChildStdout

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

impl AsFd for FileDesc

impl AsFd for std::sys::fs::unix::File

impl AsFd for Socket

impl AsFd for PidFd

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

impl AsFd for UnixDatagram

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

impl AsFd for UnixListener

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

impl AsFd for UnixStream

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

impl AsFd for BorrowedFd<'_>

impl AsFd for OwnedFd

impl<'a> AsFd for StderrLock<'a>

impl<'a> AsFd for StdinLock<'a>

impl<'a> AsFd for StdoutLock<'a>

impl<T: AsFd + ?Sized> AsFd for &T

impl<T: AsFd + ?Sized> AsFd for &mut T

impl<T: AsFd + ?Sized> AsFd for Box<T>

impl<T: AsFd + ?Sized> AsFd for Rc<T>

impl<T: AsFd + ?Sized> AsFd for UniqueRc<T>

impl<T: AsFd + ?Sized> AsFd for Arc<T>

This impl allows implementing traits that require AsFd on Arc.

use std::net::UdpSocket;
use std::sync::Arc;

trait MyTrait: AsFd {}
impl MyTrait for Arc<UdpSocket> {}
impl MyTrait for Box<UdpSocket> {}