BorrowedFd in std::os::fd - Rust
Description: A borrowed file descriptor.

## BorrowedFd

# Struct BorrowedFd

1.66.0 · Source

    pub struct BorrowedFd<'fd> { /* private fields */ }

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

A borrowed file descriptor.

This has a lifetime parameter to tie it to the lifetime of something that owns the file descriptor. For the duration of that lifetime, it is guaranteed that nobody will close the file descriptor.

This uses `repr(transparent)` and has the representation of a host file descriptor, so it can be used in FFI in places where a file descriptor is passed as an argument, it is not captured or consumed, and it never has the value `-1`.

This type does not have a `ToOwned` implementation. Calling `.to_owned()` on a variable of this type will call it on `&BorrowedFd` and use `Clone::clone()` like `ToOwned` does for all types implementing `Clone`. The result will be descriptor borrowed under the same lifetime.

To obtain an `OwnedFd`, you can use `BorrowedFd::try_clone_to_owned` instead, but this is not supported on all platforms.

## Implementations§

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### impl BorrowedFd<'_>

1.63.0 (const: 1.63.0) · Source

#### pub const unsafe fn borrow_raw(fd: RawFd) -> Self

Returns a `BorrowedFd` holding the given raw file descriptor.

##### §Safety

The resource pointed to by `fd` must remain open for the duration of the returned `BorrowedFd`.

##### §Panics

Panics if the raw file descriptor has the value `-1`.

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### impl BorrowedFd<'_>

1.63.0 · Source

#### pub fn try_clone_to_owned(&self) -> Result<OwnedFd>

Available on WebAssembly or HermitCore or `target_os=trusty` only.

Creates a new `OwnedFd` instance that shares the same underlying file description as the existing `BorrowedFd` instance.

## Trait Implementations§

1.63.0 · Source§

### impl AsFd for BorrowedFd<'_>

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

Borrows the file descriptor. Read more
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### impl AsRawFd for BorrowedFd<'_>

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#### fn as_raw_fd(&self) -> RawFd

Extracts the raw file descriptor. Read more
1.63.0 · Source§

### impl<'fd> Clone for BorrowedFd<'fd>

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#### fn clone(&self) -> BorrowedFd<'fd>

Returns a duplicate of the value. Read more
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#### fn clone_from(&mut self, source: &Self)

Performs copy-assignment from `source`. Read more
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### impl Debug for BorrowedFd<'_>

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

Formats the value using the given formatter. Read more
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### impl IsTerminal for BorrowedFd<'_>

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#### fn is_terminal(&self) -> bool

Returns `true` if the descriptor/handle refers to a terminal/tty. Read more
1.63.0 · Source§

### impl<'fd> Copy for BorrowedFd<'fd>

## Auto Trait Implementations§

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### impl<'fd> Freeze for BorrowedFd<'fd>

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### impl<'fd> RefUnwindSafe for BorrowedFd<'fd>

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### impl<'fd> Send for BorrowedFd<'fd>

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### impl<'fd> Sync for BorrowedFd<'fd>

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### impl<'fd> Unpin for BorrowedFd<'fd>

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### impl<'fd> UnwindSafe for BorrowedFd<'fd>

## Blanket Implementations§

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### impl<T> Any for T
where T: 'static + ?Sized,

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#### fn type_id(&self) -> TypeId

Gets the `TypeId` of `self`. Read more
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### impl<T> Borrow<T> for T
where T: ?Sized,

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#### fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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### impl<T> BorrowMut<T> for T
where T: ?Sized,

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#### fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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### impl<T> CloneToUninit for T
where T: Clone,

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#### unsafe fn clone_to_uninit(&self, dest: *mut u8)

🔬This is a nightly-only experimental API. (`clone_to_uninit` #126799)
Performs copy-assignment from `self` to `dest`. Read more
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### impl<T> From<T> for T

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#### fn from(t: T) -> T

Returns the argument unchanged.

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### impl<T, U> Into<U> for T
where U: From<T>,

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#### fn into(self) -> U

Calls `U::from(self)`.

That is, this conversion is whatever the implementation of `From<T> for U` chooses to do.

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### impl<T> ToOwned for T
where T: Clone,

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#### type Owned = T

The resulting type after obtaining ownership.
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#### fn to_owned(&self) -> T

Creates owned data from borrowed data, usually by cloning. Read more
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#### fn clone_into(&self, target: &mut T)

Uses borrowed data to replace owned data, usually by cloning. Read more
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### impl<T, U> TryFrom<U> for T
where U: Into<T>,

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#### type Error = Infallible

The type returned in the event of a conversion error.
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#### fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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### impl<T, U> TryInto<U> for T
where U: TryFrom<T>,

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#### type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
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#### fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.