Trait AsRawFd

pub trait AsRawFd {
    // Required method
    fn as_raw_fd(&self) -> RawFd;
}

A trait to extract the raw file descriptor from an underlying object.

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

Required Methods

fn as_raw_fd(&self) -> RawFd

Extracts the raw file descriptor.

This function is typically used to borrow an owned file descriptor. When used in this way, this method does not pass ownership of the raw file descriptor to the caller, and the file descriptor is only guaranteed to be valid while the original object has not yet been destroyed.

However, borrowing is not strictly required. See [AsFd::as_fd] for an API which strictly borrows a file descriptor.

Example

use std::fs::File;
#[cfg(any(unix, target_os = "wasi"))]
use std::os::fd::{AsRawFd, RawFd};

let mut f = File::open("foo.txt")?;
// Note that `raw_fd` is only valid as long as `f` exists.
#[cfg(any(unix, target_os = "wasi"))]
let raw_fd: RawFd = f.as_raw_fd();

Implementors

impl AsRawFd for File

impl AsRawFd for Stderr

impl AsRawFd for Stdin

impl AsRawFd for Stdout

impl AsRawFd for TcpListener

impl AsRawFd for TcpStream

impl AsRawFd for UdpSocket

impl AsRawFd for BorrowedFd<'_>

impl AsRawFd for OwnedFd

impl AsRawFd for RawFd

impl<'a> AsRawFd for StderrLock<'a>

impl<'a> AsRawFd for StdinLock<'a>

impl<'a> AsRawFd for StdoutLock<'a>

impl<T: AsRawFd> AsRawFd for Box<T>

impl<T: AsRawFd> AsRawFd for Rc<T>

impl<T: AsRawFd> AsRawFd for Arc<T>

This impl allows implementing traits that require AsRawFd on Arc.

use std::net::UdpSocket;
use std::sync::Arc;
trait MyTrait: AsRawFd {
}
impl MyTrait for Arc<UdpSocket> {}
impl MyTrait for Box<UdpSocket> {}