# Struct alloc::boxed::Box 1.0.0 [−] [src]

    pub struct Box<T: ?Sized>(_);

A pointer type for heap allocation.

See the module-level documentation for more.

## Methods

### `impl<T> Box<T>`
[src]

#### `fn new(x: T) -> Box<T>`

Allocates memory on the heap and then places `x` into it.

# Examples

    let five = Box::new(5);

### `impl<T: ?Sized> Box<T>`
[src]

#### `unsafe fn from_raw(raw: *mut T) -> Self`
1.4.0

Constructs a box from a raw pointer.

After calling this function, the raw pointer is owned by the resulting `Box`. Specifically, the `Box` destructor will call the destructor of `T` and free the allocated memory. Since the way `Box` allocates and releases memory is unspecified, the only valid pointer to pass to this function is the one taken from another `Box` via the `Box::into_raw` function.

This function is unsafe because improper use may lead to memory problems. For example, a double-free may occur if the function is called twice on the same raw pointer.

#### `fn into_raw(b: Box<T>) -> *mut T`
1.4.0

Consumes the `Box`, returning the wrapped raw pointer.

After calling this function, the caller is responsible for the memory previously managed by the `Box`. In particular, the caller should properly destroy `T` and release the memory. The proper way to do so is to convert the raw pointer back into a `Box` with the `Box::from_raw` function.

# Examples

    let seventeen = Box::new(17);
    let raw = Box::into_raw(seventeen);
    let boxed_again = unsafe { Box::from_raw(raw) };

### `impl Box<Any>`
[src]

#### `fn downcast<T: Any>(self) -> Result<Box<T>, Box<Any>>`

Attempt to downcast the box to a concrete type.

### `impl Box<Any + Send>`
[src]

#### `fn downcast<T: Any>(self) -> Result<Box<T>, Box<Any + Send>>`

Attempt to downcast the box to a concrete type.

## Trait Implementations

### `impl<T> Boxed for Box<T>`
[src]

#### `type Data = T`

Unstable (`placement_new_protocol` #27779)

#### `type Place = IntermediateBox<T>`

Unstable (`placement_new_protocol` #27779)

#### `unsafe fn finalize(b: IntermediateBox<T>) -> Box<T>`

Unstable (`placement_new_protocol` #27779)

### `impl<T: Default> Default for Box<T>`
[src]

#### `fn default() -> Box<T>`

### `impl<T> Default for Box<[T]>`
[src]

#### `fn default() -> Box<[T]>`

### `impl<T: Clone> Clone for Box<T>`
[src]

#### `fn clone(&self) -> Box<T>`

Returns a new box with a `clone()` of this box's contents.

# Examples

    let x = Box::new(5);
    let y = x.clone();

#### `fn clone_from(&mut self, source: &Box<T>)`

Copies `source`'s contents into `self` without creating a new allocation.

# Examples

    let x = Box::new(5);
    let mut y = Box::new(10);

    y.clone_from(&x);

    assert_eq!(*y, 5);

### `impl Clone for Box<str>`
1.3.0
[src]

#### `fn clone(&self) -> Self`

#### `fn clone_from(&mut self, source: &Self)`

### `impl<T: ?Sized + PartialEq> PartialEq for Box<T>`
[src]

#### `fn eq(&self, other: &Box<T>) -> bool`

#### `fn ne(&self, other: &Box<T>) -> bool`

### `impl<T: ?Sized + PartialOrd> PartialOrd for Box<T>`
[src]

#### `fn partial_cmp(&self, other: &Box<T>) -> Option<Ordering>`

#### `fn lt(&self, other: &Box<T>) -> bool`

#### `fn le(&self, other: &Box<T>) -> bool`

#### `fn ge(&self, other: &Box<T>) -> bool`

#### `fn gt(&self, other: &Box<T>) -> bool`

### `impl<T: ?Sized + Ord> Ord for Box<T>`
[src]

#### `fn cmp(&self, other: &Box<T>) -> Ordering`

### `impl<T: ?Sized + Eq> Eq for Box<T>`
[src]

### `impl<T: ?Sized + Hash> Hash for Box<T>`
[src]

#### `fn hash<H: Hasher>(&self, state: &mut H)`

#### `fn hash_slice<H>(data: &[Self], state: &mut H) where H: Hasher`
1.3.0

### `impl<T> From<T> for Box<T>`
1.6.0
[src]

#### `fn from(t: T) -> Self`

### `impl<T: Display + ?Sized> Display for Box<T>`
[src]

#### `fn fmt(&self, f: &mut Formatter) -> Result`

### `impl<T: Debug + ?Sized> Debug for Box<T>`
[src]

#### `fn fmt(&self, f: &mut Formatter) -> Result`

### `impl<T: ?Sized> Pointer for Box<T>`
[src]

#### `fn fmt(&self, f: &mut Formatter) -> Result`

### `impl<T: ?Sized> Deref for Box<T>`
[src]

#### `type Target = T`

#### `fn deref(&self) -> &T`

### `impl<T: ?Sized> DerefMut for Box<T>`
[src]

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

### `impl<I: Iterator + ?Sized> Iterator for Box<I>`
[src]

#### `type Item = I::Item`

#### `fn next(&mut self) -> Option<I::Item>`

#### `fn size_hint(&self) -> (usize, Option<usize>)`

#### `fn count(self) -> usize`

#### `fn last(self) -> Option<Self::Item>`

#### `fn nth(&mut self, n: usize) -> Option<Self::Item>`

#### `fn chain<U>(self, other: U) -> Chain<Self, U::IntoIter> where U: IntoIterator<Item=Self::Item>`

#### `fn zip<U>(self, other: U) -> Zip<Self, U::IntoIter> where U: IntoIterator`

#### `fn map<B, F>(self, f: F) -> Map<Self, F> where F: FnMut(Self::Item) -> B`

#### `fn filter<P>(self, predicate: P) -> Filter<Self, P> where P: FnMut(&Self::Item) -> bool`

#### `fn filter_map<B, F>(self, f: F) -> FilterMap<Self, F> where F: FnMut(Self::Item) -> Option<B>`

#### `fn enumerate(self) -> Enumerate<Self>`

#### `fn peekable(self) -> Peekable<Self>`

#### `fn skip_while<P>(self, predicate: P) -> SkipWhile<Self, P> where P: FnMut(&Self::Item) -> bool`

#### `fn take_while<P>(self, predicate: P) -> TakeWhile<Self, P> where P: FnMut(&Self::Item) -> bool`

#### `fn skip(self, n: usize) -> Skip<Self>`

#### `fn take(self, n: usize) -> Take<Self>`

#### `fn scan<St, B, F>(self, initial_state: St, f: F) -> Scan<Self, St, F> where F: FnMut(&mut St, Self::Item) -> Option<B>`

#### `fn flat_map<U, F>(self, f: F) -> FlatMap<Self, U, F> where F: FnMut(Self::Item) -> U, U: IntoIterator`

#### `fn fuse(self) -> Fuse<Self>`

#### `fn inspect<F>(self, f: F) -> Inspect<Self, F> where F: FnMut(&Self::Item) -> ()`

#### `fn by_ref(&mut self) -> &mut Self`

#### `fn collect<B>(self) -> B where B: FromIterator<Self::Item>`

#### `fn partition<B, F>(self, f: F) -> (B, B) where B: Default + Extend<Self::Item>, F: FnMut(&Self::Item) -> bool`

#### `fn fold<B, F>(self, init: B, f: F) -> B where F: FnMut(B, Self::Item) -> B`

#### `fn all<F>(&mut self, f: F) -> bool where F: FnMut(Self::Item) -> bool`

#### `fn any<F>(&mut self, f: F) -> bool where F: FnMut(Self::Item) -> bool`

#### `fn find<P>(&mut self, predicate: P) -> Option<Self::Item> where P: FnMut(&Self::Item) -> bool`

#### `fn position<P>(&mut self, predicate: P) -> Option<usize> where P: FnMut(Self::Item) -> bool`

#### `fn rposition<P>(&mut self, predicate: P) -> Option<usize> where P: FnMut(Self::Item) -> bool, Self: ExactSizeIterator + DoubleEndedIterator`

#### `fn max(self) -> Option<Self::Item> where Self::Item: Ord`

#### `fn min(self) -> Option<Self::Item> where Self::Item: Ord`

#### `fn max_by_key<B, F>(self, f: F) -> Option<Self::Item> where B: Ord, F: FnMut(&Self::Item) -> B`
1.6.0

#### `fn min_by_key<B, F>(self, f: F) -> Option<Self::Item> where B: Ord, F: FnMut(&Self::Item) -> B`
1.6.0

#### `fn rev(self) -> Rev<Self> where Self: DoubleEndedIterator`

#### `fn unzip<A, B, FromA, FromB>(self) -> (FromA, FromB) where FromA: Default + Extend<A>, FromB: Default + Extend<B>, Self: Iterator<Item=(A, B)>`

#### `fn cloned<'a, T>(self) -> Cloned<Self> where Self: Iterator<Item=&'a T>, T: 'a + Clone`

#### `fn cycle(self) -> Cycle<Self> where Self: Clone`

#### `fn sum<S>(self) -> S where S: Add<Self::Item, Output=S> + Zero`

#### `fn product<P>(self) -> P where P: Mul<Self::Item, Output=P> + One`

#### `fn cmp<I>(self, other: I) -> Ordering where I: IntoIterator<Item=Self::Item>, Self::Item: Ord`
1.5.0

#### `fn partial_cmp<I>(self, other: I) -> Option<Ordering> where I: IntoIterator, Self::Item: PartialOrd<I::Item>`
1.5.0

#### `fn eq<I>(self, other: I) -> bool where I: IntoIterator, Self::Item: PartialEq<I::Item>`
1.5.0

#### `fn ne<I>(self, other: I) -> bool where I: IntoIterator, Self::Item: PartialEq<I::Item>`
1.5.0

#### `fn lt<I>(self, other: I) -> bool where I: IntoIterator, Self::Item: PartialOrd<I::Item>`
1.5.0

#### `fn le<I>(self, other: I) -> bool where I: IntoIterator, Self::Item: PartialOrd<I::Item>`
1.5.0

#### `fn gt<I>(self, other: I) -> bool where I: IntoIterator, Self::Item: PartialOrd<I::Item>`
1.5.0

#### `fn ge<I>(self, other: I) -> bool where I: IntoIterator, Self::Item: PartialOrd<I::Item>`
1.5.0

### `impl<I: DoubleEndedIterator + ?Sized> DoubleEndedIterator for Box<I>`
[src]

#### `fn next_back(&mut self) -> Option<I::Item>`

### `impl<I: ExactSizeIterator + ?Sized> ExactSizeIterator for Box<I>`
[src]

#### `fn len(&self) -> usize`

### `impl<'a, A, R> FnOnce<A> for Box<FnBox<A, Output=R> + 'a>`
[src]

#### `type Output = R`

Unstable (`fnbox` #28796)

: will be deprecated if and when Box becomes usable

#### `extern "rust-call" fn call_once(self, args: A) -> R`

Unstable (`fnbox` #28796)

: will be deprecated if and when Box becomes usable

### `impl<'a, A, R> FnOnce<A> for Box<FnBox<A, Output=R> + Send + 'a>`
[src]

#### `type Output = R`

Unstable (`fnbox` #28796)

: will be deprecated if and when Box becomes usable

#### `extern "rust-call" fn call_once(self, args: A) -> R`

Unstable (`fnbox` #28796)

: will be deprecated if and when Box becomes usable

### `impl<T: ?Sized + Unsize<U>, U: ?Sized> CoerceUnsized<Box<U>> for Box<T>`
[src]

### `impl<T: Clone> Clone for Box<[T]>`
1.3.0
[src]

#### `fn clone(&self) -> Self`

#### `fn clone_from(&mut self, source: &Self)`

### `impl<T: ?Sized> Borrow<T> for Box<T>`
[src]

#### `fn borrow(&self) -> &T`

### `impl<T: ?Sized> BorrowMut<T> for Box<T>`
[src]

#### `fn borrow_mut(&mut self) -> &mut T`

### `impl<T: ?Sized> AsRef<T> for Box<T>`
1.5.0
[src]

#### `fn as_ref(&self) -> &T`

### `impl<T: ?Sized> AsMut<T> for Box<T>`
1.5.0
[src]

#### `fn as_mut(&mut self) -> &mut T`

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