AsRawFd in std::os::fd - Rust
Description: A trait to extract the raw file descriptor from an underlying object.

## AsRawFd

# Trait AsRawFd

1.66.0 · Source

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

Available on Unix or HermitCore or `target_os=trusty` or WASI or `target_os=motor` only.
Expand description

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§

1.0.0 · Source

#### 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§

1.0.0 · Source§

### impl AsRawFd for File

Available on non-`target_os=trusty` only.
1.87.0 · Source§

### impl AsRawFd for PipeReader

Available on non-`target_os=trusty` only.
1.87.0 · Source§

### impl AsRawFd for PipeWriter

Available on non-`target_os=trusty` only.
1.21.0 · Source§

### impl AsRawFd for Stderr

1.21.0 · Source§

### impl AsRawFd for Stdin

Available on non-`target_os=trusty` only.
1.21.0 · Source§

### impl AsRawFd for Stdout

1.0.0 · Source§

### impl AsRawFd for TcpListener

Available on non-`target_os=trusty` only.
1.0.0 · Source§

### impl AsRawFd for TcpStream

Available on non-`target_os=trusty` only.
1.0.0 · Source§

### impl AsRawFd for UdpSocket

Available on non-`target_os=trusty` only.
1.63.0 · Source§

### impl AsRawFd for BorrowedFd<'_>

1.63.0 · Source§

### impl AsRawFd for OwnedFd

1.48.0 · Source§

### impl AsRawFd for RawFd

1.35.0 · Source§

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

1.35.0 · Source§

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

Available on non-`target_os=trusty` only.
1.35.0 · Source§

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

Source§

### impl<T: AsRawFd + ?Sized> AsRawFd for UniqueRc<T>

1.63.0 · Source§

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

1.69.0 · Source§

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

1.63.0 · Source§

### 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> {}