Struct alloc::boxed::ThinBox

pub struct ThinBox<T: ?Sized> {
    ptr: WithOpaqueHeader,
    _marker: PhantomData<T>,
}

🔬This is a nightly-only experimental API. (thin_box #92791)

ThinBox.

A thin pointer for heap allocation, regardless of T.

Examples

#![feature(thin_box)]
use std::boxed::ThinBox;

let five = ThinBox::new(5);
let thin_slice = ThinBox::<[i32]>::new_unsize([1, 2, 3, 4]);

use std::mem::{size_of, size_of_val};
let size_of_ptr = size_of::<*const ()>();
assert_eq!(size_of_ptr, size_of_val(&five));
assert_eq!(size_of_ptr, size_of_val(&thin_slice));

Fields

ptr: WithOpaqueHeader

🔬This is a nightly-only experimental API. (thin_box #92791)

_marker: PhantomData<T>

🔬This is a nightly-only experimental API. (thin_box #92791)

Implementations

impl<T> ThinBox<T>

pub fn new(value: T) -> Self

🔬This is a nightly-only experimental API. (thin_box #92791)

Moves a type to the heap with its Metadata stored in the heap allocation instead of on the stack.

Examples

#![feature(thin_box)]
use std::boxed::ThinBox;

let five = ThinBox::new(5);

impl<Dyn: ?Sized> ThinBox<Dyn>

pub fn new_unsize<T>(value: T) -> Selfwhere T: Unsize<Dyn>,

🔬This is a nightly-only experimental API. (thin_box #92791)

Moves a type to the heap with its Metadata stored in the heap allocation instead of on the stack.

Examples

#![feature(thin_box)]
use std::boxed::ThinBox;

let thin_slice = ThinBox::<[i32]>::new_unsize([1, 2, 3, 4]);

impl<T: ?Sized> ThinBox<T>

fn meta(&self) -> <T as Pointee>::Metadata

🔬This is a nightly-only experimental API. (thin_box #92791)

fn data(&self) -> *mut u8

🔬This is a nightly-only experimental API. (thin_box #92791)

fn with_header(&self) -> &WithHeader<<T as Pointee>::Metadata>

🔬This is a nightly-only experimental API. (thin_box #92791)

Trait Implementations

impl<T: ?Sized + Debug> Debug for ThinBox<T>

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

Formats the value using the given formatter.

impl<T: ?Sized> Deref for ThinBox<T>

type Target = T

The resulting type after dereferencing.

fn deref(&self) -> &T

Dereferences the value.

impl<T: ?Sized> DerefMut for ThinBox<T>

fn deref_mut(&mut self) -> &mut T

Mutably dereferences the value.

impl<T: ?Sized + Display> Display for ThinBox<T>

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

Formats the value using the given formatter.

impl<T: ?Sized> Drop for ThinBox<T>

fn drop(&mut self)

Executes the destructor for this type.

impl<T: ?Sized + Error> Error for ThinBox<T>

fn source(&self) -> Option<&(dyn Error + 'static)>

The lower-level source of this error, if any.

fn type_id(&self, _: Internal) -> TypeIdwhere Self: 'static,

🔬This is a nightly-only experimental API. (error_type_id #60784)

Gets the TypeId of self.

fn description(&self) -> &str

👎Deprecated since 1.42.0: use the Display impl or to_string()

fn cause(&self) -> Option<&dyn Error>

👎Deprecated since 1.33.0: replaced by Error::source, which can support downcasting

fn provide<'a>(&'a self, demand: &mut Demand<'a>)

🔬This is a nightly-only experimental API. (error_generic_member_access #99301)

Provides type based access to context intended for error reports.

impl<T: ?Sized + Send> Send for ThinBox<T>

ThinBox<T> is Send if T is Send because the data is owned.

impl<T: ?Sized + Sync> Sync for ThinBox<T>

ThinBox<T> is Sync if T is Sync because the data is owned.