c_void in std::ffi - Rust
Description: Equivalent to C’s `void` type when used as a pointer.

## c_void

# Enum c_void

1.30.0 · Source

    pub enum c_void {
        // some variants omitted
    }

Expand description

Equivalent to C’s `void` type when used as a pointer.

In essence, `*const c_void` is equivalent to C’s `const void*` and `*mut c_void` is equivalent to C’s `void*`. That said, this is not the same as C’s `void` return type, which is Rust’s `()` type.

To model pointers to opaque types in FFI, until `extern type` is stabilized, it is recommended to use a newtype wrapper around an empty byte array. See the Nomicon for details.

One could use `std::os::raw::c_void` if they want to support old Rust compiler down to 1.1.0. After Rust 1.30.0, it was re-exported by this definition. For more information, please read RFC 2521.

## Trait Implementations§

1.16.0 · Source§

### impl Debug for c_void

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

Formats the value using the given formatter. Read more

## Auto Trait Implementations§

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### impl Freeze for c_void

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### impl RefUnwindSafe for c_void

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### impl Send for c_void

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### impl Sync for c_void

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### impl Unpin for c_void

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### impl UnwindSafe for c_void

## 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> 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, 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.