Struct safer_ffi::ptr::NonNullOwned

source ·

#[repr(transparent)]
pub struct NonNullOwned<T>(pub NonNull<T>, pub PhantomData<T>);

Tuple Fields§

§0: NonNull<T>§1: PhantomData<T>

Implementations§

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impl<> NonNullOwned<>

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pub unsafe fn dealloc<T>(self)

Available on crate feature alloc only.

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pub unsafe fn drop_in_place_and_dealloc<T>(self)

Available on crate feature alloc only.

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pub unsafe fn drop_in_place<T>(self)

Methods from Deref<Target = NonNull<T>>§

1.25.0 · source

pub unsafe fn as_ref<'a>(&self) -> &'a T

Returns a shared reference to the value. If the value may be uninitialized, as_uninit_ref must be used instead.

For the mutable counterpart see as_mut.

Safety

When calling this method, you have to ensure that all of the following is true:

The pointer must be properly aligned.
It must be “dereferenceable” in the sense defined in the module documentation.
The pointer must point to an initialized instance of T.
You must enforce Rust’s aliasing rules, since the returned lifetime 'a is arbitrarily chosen and does not necessarily reflect the actual lifetime of the data. In particular, while this reference exists, the memory the pointer points to must not get mutated (except inside UnsafeCell).

This applies even if the result of this method is unused! (The part about being initialized is not yet fully decided, but until it is, the only safe approach is to ensure that they are indeed initialized.)

Examples

use std::ptr::NonNull;

let mut x = 0u32;
let ptr = NonNull::new(&mut x as *mut _).expect("ptr is null!");

let ref_x = unsafe { ptr.as_ref() };
println!("{ref_x}");

1.25.0 · source

pub unsafe fn as_mut<'a>(&mut self) -> &'a mut T

Returns a unique reference to the value. If the value may be uninitialized, as_uninit_mut must be used instead.

For the shared counterpart see as_ref.

Safety

When calling this method, you have to ensure that all of the following is true:

The pointer must be properly aligned.
It must be “dereferenceable” in the sense defined in the module documentation.
The pointer must point to an initialized instance of T.
You must enforce Rust’s aliasing rules, since the returned lifetime 'a is arbitrarily chosen and does not necessarily reflect the actual lifetime of the data. In particular, while this reference exists, the memory the pointer points to must not get accessed (read or written) through any other pointer.

This applies even if the result of this method is unused! (The part about being initialized is not yet fully decided, but until it is, the only safe approach is to ensure that they are indeed initialized.)

Examples

use std::ptr::NonNull;

let mut x = 0u32;
let mut ptr = NonNull::new(&mut x).expect("null pointer");

let x_ref = unsafe { ptr.as_mut() };
assert_eq!(*x_ref, 0);
*x_ref += 2;
assert_eq!(*x_ref, 2);