pub struct NonNull<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.
Creates a new NonNull
that is dangling, but well-aligned.
This is useful for initializing types which lazily allocate, like
Vec::new
does.
Creates a new NonNull
.
ptr
must be non-null.
Creates a new NonNull
if ptr
is non-null.
Acquires the underlying *mut
pointer.
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 &*my_ptr.as_ptr()
.
[−]
Mutably 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()
.
Cast to a pointer of another type
NonNull
pointers are not Send
because the data they reference may be aliased.
NonNull
pointers are not Sync
because the data they reference may be aliased.
Performs copy-assignment from source
. Read more
Formats the value using the given formatter. Read more
Formats the value using the given formatter.
fn eq(&self, other: &Self) -> bool | [src] |
[−]
This method tests for self
and other
values to be equal, and is used by ==
. Read more
This method tests for !=
.
This method returns an Ordering
between self
and other
. Read more
[−]
Compares and returns the maximum of two values. Read more
[−]
Compares and returns the minimum of two values. Read more
This method returns an ordering between self
and other
values if one exists. Read more
This method tests less than (for self
and other
) and is used by the <
operator. Read more
This method tests less than or equal to (for self
and other
) and is used by the <=
operator. Read more
This method tests greater than (for self
and other
) and is used by the >
operator. Read more
This method tests greater than or equal to (for self
and other
) and is used by the >=
operator. Read more
Feeds this value into the given [Hasher
]. Read more
Feeds a slice of this type into the given [Hasher
]. Read more