Struct std::ptr::NonNull 1.25.0[−][src]
#[repr(transparent)]pub struct NonNull<T> where
T: ?Sized, { /* fields omitted */ }
*mut T but non-zero and covariant.
This is often the correct thing to use when building data structures using
raw pointers, but is ultimately more dangerous to use because of its additional
properties. If you're not sure if you should use NonNull<T>, just use *mut T!
Unlike *mut T, the pointer must always be non-null, even if the pointer
is never dereferenced. This is so that enums may use this forbidden value
as a discriminant -- Option<NonNull<T>> has the same size as *mut T.
However the pointer may still dangle if it isn't dereferenced.
Unlike *mut T, NonNull<T> is covariant over T. If this is incorrect
for your use case, you should include some PhantomData in your type to
provide invariance, such as PhantomData<Cell<T>> or PhantomData<&'a mut T>.
Usually this won't be necessary; covariance is correct for most safe abstractions,
such as Box, Rc, Arc, Vec, and LinkedList. This is the case because they
provide a public API that follows the normal shared XOR mutable rules of Rust.
Methods
impl<T> NonNull<T>[src]
impl<T> NonNull<T>pub fn dangling() -> NonNull<T>[src]
pub fn dangling() -> NonNull<T>Creates a new NonNull that is dangling, but well-aligned.
This is useful for initializing types which lazily allocate, like
Vec::new does.
Note that the pointer value may potentially represent a valid pointer to
a T, which means this must not be used as a "not yet initialized"
sentinel value. Types that lazily allocate must track initialization by
some other means.
impl<T> NonNull<T> where
T: ?Sized, [src]
impl<T> NonNull<T> where
T: ?Sized, pub const unsafe fn new_unchecked(ptr: *mut T) -> NonNull<T>[src]
pub const unsafe fn new_unchecked(ptr: *mut T) -> NonNull<T>pub fn new(ptr: *mut T) -> Option<NonNull<T>>[src]
pub fn new(ptr: *mut T) -> Option<NonNull<T>>Creates a new NonNull if ptr is non-null.
pub fn as_ptr(self) -> *mut T[src]
pub fn as_ptr(self) -> *mut TAcquires the underlying *mut pointer.
ⓘImportant traits for &'a mut Ipub unsafe fn as_ref(&self) -> &T[src]
pub unsafe fn as_ref(&self) -> &TDereferences the content.
The resulting lifetime is bound to self so this behaves "as if"
it were actually an instance of T that is getting borrowed. If a longer
(unbound) lifetime is needed, use &*my_ptr.as_ptr().
ⓘImportant traits for &'a mut Ipub unsafe fn as_mut(&mut self) -> &mut T[src]
pub unsafe fn as_mut(&mut self) -> &mut TMutably dereferences the content.
The resulting lifetime is bound to self so this behaves "as if"
it were actually an instance of T that is getting borrowed. If a longer
(unbound) lifetime is needed, use &mut *my_ptr.as_ptr().
pub fn cast<U>(self) -> NonNull<U>1.27.0[src]
pub fn cast<U>(self) -> NonNull<U>Cast to a pointer of another type
Trait Implementations
impl<T> Hash for NonNull<T> where
T: ?Sized, [src]
impl<T> Hash for NonNull<T> where
T: ?Sized, fn hash<H>(&self, state: &mut H) where
H: Hasher, [src]
fn hash<H>(&self, state: &mut H) where
H: Hasher, Feeds this value into the given [Hasher]. Read more
fn hash_slice<H>(data: &[Self], state: &mut H) where
H: Hasher, 1.3.0[src]
fn hash_slice<H>(data: &[Self], state: &mut H) where
H: Hasher, Feeds a slice of this type into the given [Hasher]. Read more
impl<T> From<Unique<T>> for NonNull<T> where
T: ?Sized, [src]
impl<T> From<Unique<T>> for NonNull<T> where
T: ?Sized, impl<'a, T> From<&'a T> for NonNull<T> where
T: ?Sized, [src]
impl<'a, T> From<&'a T> for NonNull<T> where
T: ?Sized, impl<'a, T> From<&'a mut T> for NonNull<T> where
T: ?Sized, [src]
impl<'a, T> From<&'a mut T> for NonNull<T> where
T: ?Sized, impl<T> Pointer for NonNull<T> where
T: ?Sized, [src]
impl<T> Pointer for NonNull<T> where
T: ?Sized, fn fmt(&self, f: &mut Formatter) -> Result<(), Error>[src]
fn fmt(&self, f: &mut Formatter) -> Result<(), Error>Formats the value using the given formatter.
impl<T> Clone for NonNull<T> where
T: ?Sized, [src]
impl<T> Clone for NonNull<T> where
T: ?Sized, fn clone(&self) -> NonNull<T>[src]
fn clone(&self) -> NonNull<T>Returns a copy of the value. Read more
fn clone_from(&mut self, source: &Self)1.0.0[src]
fn clone_from(&mut self, source: &Self)Performs copy-assignment from source. Read more
impl<T> Debug for NonNull<T> where
T: ?Sized, [src]
impl<T> Debug for NonNull<T> where
T: ?Sized, fn fmt(&self, f: &mut Formatter) -> Result<(), Error>[src]
fn fmt(&self, f: &mut Formatter) -> Result<(), Error>Formats the value using the given formatter. Read more
impl<T> PartialOrd<NonNull<T>> for NonNull<T> where
T: ?Sized, [src]
impl<T> PartialOrd<NonNull<T>> for NonNull<T> where
T: ?Sized, fn partial_cmp(&self, other: &NonNull<T>) -> Option<Ordering>[src]
fn partial_cmp(&self, other: &NonNull<T>) -> Option<Ordering>This method returns an ordering between self and other values if one exists. Read more
#[must_use]
fn lt(&self, other: &Rhs) -> bool1.0.0[src]
#[must_use]
fn lt(&self, other: &Rhs) -> boolThis method tests less than (for self and other) and is used by the < operator. Read more
#[must_use]
fn le(&self, other: &Rhs) -> bool1.0.0[src]
#[must_use]
fn le(&self, other: &Rhs) -> boolThis method tests less than or equal to (for self and other) and is used by the <= operator. Read more
#[must_use]
fn gt(&self, other: &Rhs) -> bool1.0.0[src]
#[must_use]
fn gt(&self, other: &Rhs) -> boolThis method tests greater than (for self and other) and is used by the > operator. Read more
#[must_use]
fn ge(&self, other: &Rhs) -> bool1.0.0[src]
#[must_use]
fn ge(&self, other: &Rhs) -> boolThis method tests greater than or equal to (for self and other) and is used by the >= operator. Read more
impl<T> Ord for NonNull<T> where
T: ?Sized, [src]
impl<T> Ord for NonNull<T> where
T: ?Sized, fn cmp(&self, other: &NonNull<T>) -> Ordering[src]
fn cmp(&self, other: &NonNull<T>) -> OrderingThis method returns an Ordering between self and other. Read more
fn max(self, other: Self) -> Self1.21.0[src]
fn max(self, other: Self) -> SelfCompares and returns the maximum of two values. Read more
fn min(self, other: Self) -> Self1.21.0[src]
fn min(self, other: Self) -> SelfCompares and returns the minimum of two values. Read more
impl<T> Eq for NonNull<T> where
T: ?Sized, [src]
impl<T> Eq for NonNull<T> where
T: ?Sized, impl<T, U> CoerceUnsized<NonNull<U>> for NonNull<T> where
T: Unsize<U> + ?Sized,
U: ?Sized, [src]
impl<T, U> CoerceUnsized<NonNull<U>> for NonNull<T> where
T: Unsize<U> + ?Sized,
U: ?Sized, impl<T> PartialEq<NonNull<T>> for NonNull<T> where
T: ?Sized, [src]
impl<T> PartialEq<NonNull<T>> for NonNull<T> where
T: ?Sized, fn eq(&self, other: &NonNull<T>) -> bool[src]
fn eq(&self, other: &NonNull<T>) -> boolThis method tests for self and other values to be equal, and is used by ==. Read more
#[must_use]
fn ne(&self, other: &Rhs) -> bool1.0.0[src]
#[must_use]
fn ne(&self, other: &Rhs) -> boolThis method tests for !=.
impl<T> Copy for NonNull<T> where
T: ?Sized, [src]
impl<T> Copy for NonNull<T> where
T: ?Sized, impl<T> !Sync for NonNull<T> where
T: ?Sized, [src]
impl<T> !Sync for NonNull<T> where
T: ?Sized, NonNull pointers are not Sync because the data they reference may be aliased.
impl<T> !Send for NonNull<T> where
T: ?Sized, [src]
impl<T> !Send for NonNull<T> where
T: ?Sized, NonNull pointers are not Send because the data they reference may be aliased.
impl<T: RefUnwindSafe + ?Sized> UnwindSafe for NonNull<T>[src]
impl<T: RefUnwindSafe + ?Sized> UnwindSafe for NonNull<T>