std::os::fd::raw

Trait FromRawFd

1.66.0 · Source

pub trait FromRawFd {
    // Required method
    unsafe fn from_raw_fd(fd: RawFd) -> Self;
}

Available on Unix or HermitCore or target_os=trusty or WASI only.

Expand description

A trait to express the ability to construct an object from a raw file descriptor.

Required Methods§

1.1.0 · Source

unsafe fn from_raw_fd(fd: RawFd) -> Self

Constructs a new instance of Self from the given raw file descriptor.

This function is typically used to consume ownership of the specified file descriptor. When used in this way, the returned object will take responsibility for closing it when the object goes out of scope.

However, consuming ownership is not strictly required. Use a From<OwnedFd>::from implementation for an API which strictly consumes ownership.

§Safety

The fd passed in must be an owned file descriptor; in particular, it must be open.

§Example

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

let f = File::open("foo.txt")?;
let raw_fd: RawFd = f.into_raw_fd();
// SAFETY: no other functions should call `from_raw_fd`, so there
// is only one owner for the file descriptor.
let f = unsafe { File::from_raw_fd(raw_fd) };