#[repr(transparent)]pub struct Unique<T>where
T: ?Sized,{
pointer: NonNull<T>,
_marker: PhantomData<T>,
}ptr_internals)Expand description
A wrapper around a raw non-null *mut T that indicates that the possessor
of this wrapper owns the referent. Useful for building abstractions like
Box<T>, Vec<T>, String, and HashMap<K, V>.
Unlike *mut T, Unique<T> behaves “as if” it were an instance of T.
It implements Send/Sync if T is Send/Sync. It also implies
the kind of strong aliasing guarantees an instance of T can expect:
the referent of the pointer should not be modified without a unique path to
its owning Unique.
If you’re uncertain of whether it’s correct to use Unique for your purposes,
consider using NonNull, which has weaker semantics.
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<Unique<T>> has the same size as Unique<T>.
However the pointer may still dangle if it isn’t dereferenced.
Unlike *mut T, Unique<T> is covariant over T. This should always be correct
for any type which upholds Unique’s aliasing requirements.
Fields§
§pointer: NonNull<T>ptr_internals)_marker: PhantomData<T>ptr_internals)