alloc::boxed::Box - Rust
Description: API documentation for the Rust `Box` struct in crate `alloc`.
Keywords: rust, rustlang, rust-lang, Box

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

    #[lang = "owned_box"]
    pub struct Box<T: ?Sized>(_);

A pointer type for heap allocation.

See the module-level documentation for more.

## Methods

###

`impl<T> Box<T>`

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####
ⓘImportant traits for Box<I>

### Important traits for Box<I>

`impl<I: Iterator + ?Sized> Iterator for Box<I> type Item = I::Item;`

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

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

This doesn't actually allocate if `T` is zero-sized.

# Examples

    let five = Box::new(5);

###

`impl<T: ?Sized> Box<T>`

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####

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

1.4.0
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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.

# Examples

    let x = Box::new(5);
    let ptr = Box::into_raw(x);
    let x = unsafe { Box::from_raw(ptr) };

####

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

1.4.0
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Consumes the `Box`, returning a wrapped raw pointer.

The pointer will be properly aligned and non-null.

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.

Note: this is an associated function, which means that you have to call it as `Box::into_raw(b)` instead of `b.into_raw()`. This is so that there is no conflict with a method on the inner type.

# Examples

    let x = Box::new(5);
    let ptr = Box::into_raw(x);

####

`pub fn into_raw_non_null(b: Box<T>) -> NonNull<T>`

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🔬 This is a nightly-only experimental API. (`box_into_raw_non_null` #47336)

Consumes the `Box`, returning the wrapped pointer as `NonNull<T>`.

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 `NonNull<T>` pointer into a raw pointer and back into a `Box` with the `Box::from_raw` function.

Note: this is an associated function, which means that you have to call it as `Box::into_raw_non_null(b)` instead of `b.into_raw_non_null()`. This is so that there is no conflict with a method on the inner type.

# Examples

    #![feature(box_into_raw_non_null)]

    fn main() {
        let x = Box::new(5);
        let ptr = Box::into_raw_non_null(x);
    }

####

`pub fn leak<'a>(b: Box<T>) -> &'a mut T where T: 'a,`

1.26.0
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Consumes and leaks the `Box`, returning a mutable reference, `&'a mut T`. Note that the type `T` must outlive the chosen lifetime `'a`. If the type has only static references, or none at all, then this may be chosen to be `'static`.

This function is mainly useful for data that lives for the remainder of the program's life. Dropping the returned reference will cause a memory leak. If this is not acceptable, the reference should first be wrapped with the `Box::from_raw` function producing a `Box`. This `Box` can then be dropped which will properly destroy `T` and release the allocated memory.

Note: this is an associated function, which means that you have to call it as `Box::leak(b)` instead of `b.leak()`. This is so that there is no conflict with a method on the inner type.

# Examples

Simple usage:

    fn main() {
        let x = Box::new(41);
        let static_ref: &'static mut usize = Box::leak(x);
        *static_ref += 1;
        assert_eq!(*static_ref, 42);
    }

Unsized data:

    fn main() {
        let x = vec![1, 2, 3].into_boxed_slice();
        let static_ref = Box::leak(x);
        static_ref[0] = 4;
        assert_eq!(*static_ref, [4, 2, 3]);
    }

###

`impl Box<Any>`

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####

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

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Attempt to downcast the box to a concrete type.

# Examples

    use std::any::Any;

    fn print_if_string(value: Box<Any>) {
        if let Ok(string) = value.downcast::<String>() {
            println!("String ({}): {}", string.len(), string);
        }
    }

    fn main() {
        let my_string = "Hello World".to_string();
        print_if_string(Box::new(my_string));
        print_if_string(Box::new(0i8));
    }

###

`impl Box<Any + Send>`

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####

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

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Attempt to downcast the box to a concrete type.

# Examples

    use std::any::Any;

    fn print_if_string(value: Box<Any + Send>) {
        if let Ok(string) = value.downcast::<String>() {
            println!("String ({}): {}", string.len(), string);
        }
    }

    fn main() {
        let my_string = "Hello World".to_string();
        print_if_string(Box::new(my_string));
        print_if_string(Box::new(0i8));
    }

## Trait Implementations

###

`impl<T: ?Sized> Drop for Box<T>`

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####

`fn drop(&mut self)`

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Executes the destructor for this type. Read more

###

`impl<T: Default> Default for Box<T>`

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####
ⓘImportant traits for Box<I>

### Important traits for Box<I>

`impl<I: Iterator + ?Sized> Iterator for Box<I> type Item = I::Item;`

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

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Creates a `Box<T>`, with the `Default` value for T.

###

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

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####
ⓘImportant traits for Box<I>

### Important traits for Box<I>

`impl<I: Iterator + ?Sized> Iterator for Box<I> type Item = I::Item;`

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

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Returns the "default value" for a type. Read more

###

`impl Default for Box<str>`

1.17.0
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####
ⓘImportant traits for Box<I>

### Important traits for Box<I>

`impl<I: Iterator + ?Sized> Iterator for Box<I> type Item = I::Item;`

`fn default() -> Box<str>`

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Returns the "default value" for a type. Read more

###

`impl<T: Clone> Clone for Box<T>`

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####
ⓘImportant traits for Box<I>

### Important traits for Box<I>

`impl<I: Iterator + ?Sized> Iterator for Box<I> type Item = I::Item;`

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

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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>)`

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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
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####

`fn clone(&self) -> Self`

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Returns a copy of the value. Read more

####

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

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Performs copy-assignment from `source`. Read more

###

`impl<T: ?Sized + PartialEq> PartialEq for Box<T>`

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####

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

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This method tests for `self` and `other` values to be equal, and is used by `==`. Read more

####

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

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This method tests for `!=`.

###

`impl<T: ?Sized + PartialOrd> PartialOrd for Box<T>`

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####

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

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This method returns an ordering between `self` and `other` values if one exists. Read more

####

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

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This method tests less than (for `self` and `other`) and is used by the `<` operator. Read more

####

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

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This method tests less than or equal to (for `self` and `other`) and is used by the `<=` operator. Read more

####

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

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This method tests greater than or equal to (for `self` and `other`) and is used by the `>=` operator. Read more

####

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

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This method tests greater than (for `self` and `other`) and is used by the `>` operator. Read more

###

`impl<T: ?Sized + Ord> Ord for Box<T>`

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####

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

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This method returns an `Ordering` between `self` and `other`. Read more

####

`fn max(self, other: Self) -> Self`

1.21.0
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Compares and returns the maximum of two values. Read more

####

`fn min(self, other: Self) -> Self`

1.21.0
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Compares and returns the minimum of two values. Read more

###

`impl<T: ?Sized + Eq> Eq for Box<T>`

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###

`impl<T: ?Sized + Hash> Hash for Box<T>`

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####

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

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Feeds this value into the given [`Hasher`]. Read more

####

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

1.3.0
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Feeds a slice of this type into the given [`Hasher`]. Read more

###

`impl<T: ?Sized + Hasher> Hasher for Box<T>`

1.22.0
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####

`fn finish(&self) -> u64`

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Returns the hash value for the values written so far. Read more

####

`fn write(&mut self, bytes: &[u8])`

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Writes some data into this `Hasher`. Read more

####

`fn write_u8(&mut self, i: u8)`

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Writes a single `u8` into this hasher.

####

`fn write_u16(&mut self, i: u16)`

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Writes a single `u16` into this hasher.

####

`fn write_u32(&mut self, i: u32)`

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Writes a single `u32` into this hasher.

####

`fn write_u64(&mut self, i: u64)`

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Writes a single `u64` into this hasher.

####

`fn write_u128(&mut self, i: u128)`

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Writes a single `u128` into this hasher.

####

`fn write_usize(&mut self, i: usize)`

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Writes a single `usize` into this hasher.

####

`fn write_i8(&mut self, i: i8)`

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Writes a single `i8` into this hasher.

####

`fn write_i16(&mut self, i: i16)`

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Writes a single `i16` into this hasher.

####

`fn write_i32(&mut self, i: i32)`

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Writes a single `i32` into this hasher.

####

`fn write_i64(&mut self, i: i64)`

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Writes a single `i64` into this hasher.

####

`fn write_i128(&mut self, i: i128)`

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Writes a single `i128` into this hasher.

####

`fn write_isize(&mut self, i: isize)`

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Writes a single `isize` into this hasher.

###

`impl<T> From<T> for Box<T>`

1.6.0
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####

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

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Performs the conversion.

###

`impl<'a, T: Copy> From<&'a [T]> for Box<[T]>`

1.17.0
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####
ⓘImportant traits for Box<I>

### Important traits for Box<I>

`impl<I: Iterator + ?Sized> Iterator for Box<I> type Item = I::Item;`

`fn from(slice: &'a [T]) -> Box<[T]>`

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Performs the conversion.

###

`impl<'a> From<&'a str> for Box<str>`

1.17.0
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####
ⓘImportant traits for Box<I>

### Important traits for Box<I>

`impl<I: Iterator + ?Sized> Iterator for Box<I> type Item = I::Item;`

`fn from(s: &'a str) -> Box<str>`

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Performs the conversion.

###

`impl From<Box<str>> for Box<[u8]>`

1.19.0
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####

`fn from(s: Box<str>) -> Self`

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Performs the conversion.

###

`impl<T: Display + ?Sized> Display for Box<T>`

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####

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

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Formats the value using the given formatter. Read more

###

`impl<T: Debug + ?Sized> Debug for Box<T>`

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####

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

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Formats the value using the given formatter. Read more

###

`impl<T: ?Sized> Pointer for Box<T>`

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####

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

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Formats the value using the given formatter.

###

`impl<T: ?Sized> Deref for Box<T>`

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#### `type Target = T`

The resulting type after dereferencing.

####

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

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Dereferences the value.

###

`impl<T: ?Sized> DerefMut for Box<T>`

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####

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

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Mutably dereferences the value.

###

`impl<I: Iterator + ?Sized> Iterator for Box<I>`

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

The type of the elements being iterated over.

####

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

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Advances the iterator and returns the next value. Read more

####

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

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Returns the bounds on the remaining length of the iterator. Read more

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

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Returns the `n`th element of the iterator. Read more

####

`fn count(self) -> usize`

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Consumes the iterator, counting the number of iterations and returning it. Read more

####

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

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Consumes the iterator, returning the last element. Read more

####
ⓘImportant traits for StepBy<I>

### Important traits for StepBy<I>

`impl<I> Iterator for StepBy<I> where
I: Iterator, type Item = <I as Iterator>::Item;`

`fn step_by(self, step: usize) -> StepBy<Self>`

1.28.0
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Creates an iterator starting at the same point, but stepping by the given amount at each iteration. Read more

####
ⓘImportant traits for Chain<A, B>

### Important traits for Chain<A, B>

`impl<A, B> Iterator for Chain<A, B> where
A: Iterator,
B: Iterator<Item = <A as Iterator>::Item>, type Item = <A as Iterator>::Item;`

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

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Takes two iterators and creates a new iterator over both in sequence. Read more

####
ⓘImportant traits for Zip<A, B>

### Important traits for Zip<A, B>

`impl<A, B> Iterator for Zip<A, B> where
A: Iterator,
B: Iterator, type Item = (<A as Iterator>::Item, <B as Iterator>::Item);`

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

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'Zips up' two iterators into a single iterator of pairs. Read more

####
ⓘImportant traits for Map<I, F>

### Important traits for Map<I, F>

`impl<B, I, F> Iterator for Map<I, F> where
F: FnMut(<I as Iterator>::Item) -> B,
I: Iterator, type Item = B;`

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

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Takes a closure and creates an iterator which calls that closure on each element. Read more

####

`fn for_each<F>(self, f: F) where F: FnMut(Self::Item),`

1.21.0
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Calls a closure on each element of an iterator. Read more

####
ⓘImportant traits for Filter<I, P>

### Important traits for Filter<I, P>

`impl<I, P> Iterator for Filter<I, P> where
I: Iterator,
P: FnMut(&<I as Iterator>::Item) -> bool, type Item = <I as Iterator>::Item;`

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

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Creates an iterator which uses a closure to determine if an element should be yielded. Read more

####
ⓘImportant traits for FilterMap<I, F>

### Important traits for FilterMap<I, F>

`impl<B, I, F> Iterator for FilterMap<I, F> where
F: FnMut(<I as Iterator>::Item) -> Option<B>,
I: Iterator, type Item = B;`

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

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Creates an iterator that both filters and maps. Read more

####
ⓘImportant traits for Enumerate<I>

### Important traits for Enumerate<I>

`impl<I> Iterator for Enumerate<I> where
I: Iterator, type Item = (usize, <I as Iterator>::Item);`

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

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Creates an iterator which gives the current iteration count as well as the next value. Read more

####
ⓘImportant traits for Peekable<I>

### Important traits for Peekable<I>

`impl<I> Iterator for Peekable<I> where
I: Iterator, type Item = <I as Iterator>::Item;`

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

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Creates an iterator which can use `peek` to look at the next element of the iterator without consuming it. Read more

####
ⓘImportant traits for SkipWhile<I, P>

### Important traits for SkipWhile<I, P>

`impl<I, P> Iterator for SkipWhile<I, P> where
I: Iterator,
P: FnMut(&<I as Iterator>::Item) -> bool, type Item = <I as Iterator>::Item;`

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

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Creates an iterator that [`skip`]s elements based on a predicate. Read more

####
ⓘImportant traits for TakeWhile<I, P>

### Important traits for TakeWhile<I, P>

`impl<I, P> Iterator for TakeWhile<I, P> where
I: Iterator,
P: FnMut(&<I as Iterator>::Item) -> bool, type Item = <I as Iterator>::Item;`

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

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Creates an iterator that yields elements based on a predicate. Read more

####
ⓘImportant traits for Skip<I>

### Important traits for Skip<I>

`impl<I> Iterator for Skip<I> where
I: Iterator, type Item = <I as Iterator>::Item;`

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

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Creates an iterator that skips the first `n` elements. Read more

####
ⓘImportant traits for Take<I>

### Important traits for Take<I>

`impl<I> Iterator for Take<I> where
I: Iterator, type Item = <I as Iterator>::Item;`

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

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Creates an iterator that yields its first `n` elements. Read more

####
ⓘImportant traits for Scan<I, St, F>

### Important traits for Scan<I, St, F>

`impl<B, I, St, F> Iterator for Scan<I, St, F> where
F: FnMut(&mut St, <I as Iterator>::Item) -> Option<B>,
I: Iterator, type Item = B;`

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

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An iterator adaptor similar to [`fold`] that holds internal state and produces a new iterator. Read more

####
ⓘImportant traits for FlatMap<I, U, F>

### Important traits for FlatMap<I, U, F>

`impl<I, U, F> Iterator for FlatMap<I, U, F> where
F: FnMut(<I as Iterator>::Item) -> U,
I: Iterator,
U: IntoIterator, type Item = <U as IntoIterator>::Item;`

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

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Creates an iterator that works like map, but flattens nested structure. Read more

####
ⓘImportant traits for Flatten<I>

### Important traits for Flatten<I>

`impl<I, U> Iterator for Flatten<I> where
I: Iterator,
U: Iterator,
<I as Iterator>::Item: IntoIterator,
<<I as Iterator>::Item as IntoIterator>::IntoIter == U,
<<I as Iterator>::Item as IntoIterator>::Item == <U as Iterator>::Item, type Item = <U as Iterator>::Item;`

`fn flatten(self) -> Flatten<Self> where Self::Item: IntoIterator,`

1.29.0
[src]

Creates an iterator that flattens nested structure. Read more

####
ⓘImportant traits for Fuse<I>

### Important traits for Fuse<I>

`impl<I> Iterator for Fuse<I> where
I: FusedIterator, impl<I> Iterator for Fuse<I> where
I: Iterator, type Item = <I as Iterator>::Item;`

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

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Creates an iterator which ends after the first [`None`]. Read more

####
ⓘImportant traits for Inspect<I, F>

### Important traits for Inspect<I, F>

`impl<I, F> Iterator for Inspect<I, F> where
F: FnMut(&<I as Iterator>::Item),
I: Iterator, type Item = <I as Iterator>::Item;`

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

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Do something with each element of an iterator, passing the value on. Read more

####

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

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Borrows an iterator, rather than consuming it. Read more

####

`#[must_use = "if you really need to exhaust the iterator, consider `.for_each(drop)` instead"] fn collect<B>(self) -> B where B: FromIterator<Self::Item>,`

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Transforms an iterator into a collection. Read more

####

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

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Consumes an iterator, creating two collections from it. Read more

####

`fn try_fold<B, F, R>(&mut self, init: B, f: F) -> R where F: FnMut(B, Self::Item) -> R, R: Try<Ok = B>,`

1.27.0
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An iterator method that applies a function as long as it returns successfully, producing a single, final value. Read more

####

`fn try_for_each<F, R>(&mut self, f: F) -> R where F: FnMut(Self::Item) -> R, R: Try<Ok = ()>,`

1.27.0
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An iterator method that applies a fallible function to each item in the iterator, stopping at the first error and returning that error. Read more

####

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

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An iterator method that applies a function, producing a single, final value. Read more

####

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

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Tests if every element of the iterator matches a predicate. Read more

####

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

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Tests if any element of the iterator matches a predicate. Read more

####

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

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Searches for an element of an iterator that satisfies a predicate. Read more

####

`fn find_map<B, F>(&mut self, f: F) -> Option<B> where F: FnMut(Self::Item) -> Option<B>,`

1.30.0
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Applies function to the elements of iterator and returns the first non-none result. Read more

####

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

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Searches for an element in an iterator, returning its index. Read more

####

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

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Searches for an element in an iterator from the right, returning its index. Read more

####

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

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Returns the maximum element of an iterator. Read more

####

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

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Returns the minimum element of an iterator. Read more

####

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

1.6.0
[src]

Returns the element that gives the maximum value from the specified function. Read more

####

`fn max_by<F>(self, compare: F) -> Option<Self::Item> where F: FnMut(&Self::Item, &Self::Item) -> Ordering,`

1.15.0
[src]

Returns the element that gives the maximum value with respect to the specified comparison function. Read more

####

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

1.6.0
[src]

Returns the element that gives the minimum value from the specified function. Read more

####

`fn min_by<F>(self, compare: F) -> Option<Self::Item> where F: FnMut(&Self::Item, &Self::Item) -> Ordering,`

1.15.0
[src]

Returns the element that gives the minimum value with respect to the specified comparison function. Read more

####
ⓘImportant traits for Rev<I>

### Important traits for Rev<I>

`impl<I> Iterator for Rev<I> where
I: DoubleEndedIterator, type Item = <I as Iterator>::Item;`

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

[src]

Reverses an iterator's direction. Read more

####

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

[src]

Converts an iterator of pairs into a pair of containers. Read more

####
ⓘImportant traits for Cloned<I>

### Important traits for Cloned<I>

`impl<'a, I, T> Iterator for Cloned<I> where
I: Iterator<Item = &'a T>,
T: 'a + Clone, type Item = T;`

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

[src]

Creates an iterator which [`clone`]s all of its elements. Read more

####
ⓘImportant traits for Cycle<I>

### Important traits for Cycle<I>

`impl<I> Iterator for Cycle<I> where
I: Clone + Iterator, type Item = <I as Iterator>::Item;`

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

[src]

Repeats an iterator endlessly. Read more

####

`fn sum<S>(self) -> S where S: Sum<Self::Item>,`

1.11.0
[src]

Sums the elements of an iterator. Read more

####

`fn product<P>(self) -> P where P: Product<Self::Item>,`

1.11.0
[src]

Iterates over the entire iterator, multiplying all the elements Read more

####

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

1.5.0
[src]

Lexicographically compares the elements of this `Iterator` with those of another. Read more

####

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

1.5.0
[src]

Lexicographically compares the elements of this `Iterator` with those of another. Read more

####

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

1.5.0
[src]

Determines if the elements of this `Iterator` are equal to those of another. Read more

####

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

1.5.0
[src]

Determines if the elements of this `Iterator` are unequal to those of another. Read more

####

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

1.5.0
[src]

Determines if the elements of this `Iterator` are lexicographically less than those of another. Read more

####

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

1.5.0
[src]

Determines if the elements of this `Iterator` are lexicographically less or equal to those of another. Read more

####

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

1.5.0
[src]

Determines if the elements of this `Iterator` are lexicographically greater than those of another. Read more

####

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

1.5.0
[src]

Determines if the elements of this `Iterator` are lexicographically greater than or equal to those of another. Read more

###

`impl<I: DoubleEndedIterator + ?Sized> DoubleEndedIterator for Box<I>`

[src]

####

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

[src]

Removes and returns an element from the end of the iterator. Read more

####

`fn try_rfold<B, F, R>(&mut self, init: B, f: F) -> R where F: FnMut(B, Self::Item) -> R, R: Try<Ok = B>,`

1.27.0
[src]

This is the reverse version of [`try_fold()`]: it takes elements starting from the back of the iterator. Read more

####

`fn rfold<B, F>(self, accum: B, f: F) -> B where F: FnMut(B, Self::Item) -> B,`

1.27.0
[src]

An iterator method that reduces the iterator's elements to a single, final value, starting from the back. Read more

####

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

1.27.0
[src]

Searches for an element of an iterator from the back that satisfies a predicate. Read more

###

`impl<I: ExactSizeIterator + ?Sized> ExactSizeIterator for Box<I>`

[src]

####

`fn len(&self) -> usize`

[src]

Returns the exact number of times the iterator will iterate. Read more

####

`fn is_empty(&self) -> bool`

[src]

🔬 This is a nightly-only experimental API. (`exact_size_is_empty` #35428)

Returns whether the iterator is empty. Read more

###

`impl<I: FusedIterator + ?Sized> FusedIterator for Box<I>`

1.26.0
[src]

###

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

[src]

#### `type Output = R`

The returned type after the call operator is used.

####

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

[src]

🔬 This is a nightly-only experimental API. (`fn_traits` #29625)

Performs the call operation.

###

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

[src]

#### `type Output = R`

The returned type after the call operator is used.

####

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

[src]

🔬 This is a nightly-only experimental API. (`fn_traits` #29625)

Performs the call operation.

###

`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`

[src]

Returns a copy of the value. Read more

####

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

[src]

Performs copy-assignment from `source`. Read more

###

`impl<T: ?Sized> Borrow<T> for Box<T>`

1.1.0
[src]

####

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

[src]

Immutably borrows from an owned value. Read more

###

`impl<T: ?Sized> BorrowMut<T> for Box<T>`

1.1.0
[src]

####

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

[src]

Mutably borrows from an owned value. Read more

###

`impl<T: ?Sized> AsRef<T> for Box<T>`

1.5.0
[src]

####

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

[src]

Performs the conversion.

###

`impl<T: ?Sized> AsMut<T> for Box<T>`

1.5.0
[src]

####

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

[src]

Performs the conversion.

###

`impl<T: ?Sized> Unpin for Box<T>`

[src]

###

`impl<T: ?Sized> Generator for Box<T> where T: Generator,`

[src]

#### `type Yield = T::Yield`

🔬 This is a nightly-only experimental API. (`generator_trait` #43122)

The type of value this generator yields. Read more

#### `type Return = T::Return`

🔬 This is a nightly-only experimental API. (`generator_trait` #43122)

The type of value this generator returns. Read more

####

`unsafe fn resume(&mut self) -> GeneratorState<Self::Yield, Self::Return>`

[src]

🔬 This is a nightly-only experimental API. (`generator_trait` #43122)

Resumes the execution of this generator. Read more

###

`impl<F: ?Sized + Future + Unpin> Future for Box<F>`

[src]

#### `type Output = F::Output`

🔬 This is a nightly-only experimental API. (`futures_api` #50547)

futures in libcore are unstable

The result of the `Future`.

####

`fn poll(self: PinMut<Self>, cx: &mut Context) -> Poll<Self::Output>`

[src]

🔬 This is a nightly-only experimental API. (`futures_api` #50547)

futures in libcore are unstable

Attempt to resolve the future to a final value, registering the current task for wakeup if the value is not yet available. Read more

###

`impl<'a, T, F> UnsafeFutureObj<'a, T> for Box<F> where F: Future<Output = T> + 'a,`

[src]

####

`fn into_raw(self) -> *mut ()`

[src]

🔬 This is a nightly-only experimental API. (`futures_api` #50547)

futures in libcore are unstable

Convert an owned instance into a (conceptually owned) void pointer.

####

`unsafe fn poll(ptr: *mut (), cx: &mut Context) -> Poll<T>`

[src]

🔬 This is a nightly-only experimental API. (`futures_api` #50547)

futures in libcore are unstable

Poll the future represented by the given void pointer. Read more

####

`unsafe fn drop(ptr: *mut ())`

[src]

🔬 This is a nightly-only experimental API. (`futures_api` #50547)

futures in libcore are unstable

Drops the future represented by the given void pointer. Read more

###

`impl<Sp: ?Sized> Spawn for Box<Sp> where Sp: Spawn,`

[src]

####

`fn spawn_obj( &mut self, future: FutureObj<'static, ()> ) -> Result<(), SpawnObjError>`

[src]

🔬 This is a nightly-only experimental API. (`futures_api` #50547)

futures in libcore are unstable

Spawns a new task with the given future. The future will be polled until completion. Read more

####

`fn status(&self) -> Result<(), SpawnErrorKind>`

[src]

🔬 This is a nightly-only experimental API. (`futures_api` #50547)

futures in libcore are unstable

Determines whether the executor is able to spawn new tasks. Read more

###

`impl<'a, F: Future<Output = ()> + Send + 'a> From<Box<F>> for FutureObj<'a, ()>`

[src]

####

`fn from(boxed: Box<F>) -> Self`

[src]

Performs the conversion.

###

`impl<'a, F: Future<Output = ()> + 'a> From<Box<F>> for LocalFutureObj<'a, ()>`

[src]

####

`fn from(boxed: Box<F>) -> Self`

[src]

Performs the conversion.

###

`impl<T: Unpin + ?Sized> From<PinBox<T>> for Box<T>`

[src]

####
ⓘImportant traits for Box<I>

### Important traits for Box<I>

`impl<I: Iterator + ?Sized> Iterator for Box<I> type Item = I::Item;`

`fn from(pinned: PinBox<T>) -> Box<T>`

[src]

Performs the conversion.

###

`impl<T: ?Sized> From<Box<T>> for Arc<T>`

1.21.0
[src]

####

`fn from(v: Box<T>) -> Arc<T>`

[src]

Performs the conversion.

###

`impl<T: ?Sized> From<Box<T>> for Rc<T>`

1.21.0
[src]

####

`fn from(v: Box<T>) -> Rc<T>`

[src]

Performs the conversion.

###

`impl<T: ?Sized> From<Box<T>> for PinBox<T>`

[src]

####

`fn from(boxed: Box<T>) -> PinBox<T>`

[src]

Performs the conversion.

###

`impl From<Box<str>> for String`

1.18.0
[src]

####

`fn from(s: Box<str>) -> String`

[src]

Performs the conversion.

###

`impl From<String> for Box<str>`

1.20.0
[src]

####
ⓘImportant traits for Box<I>

### Important traits for Box<I>

`impl<I: Iterator + ?Sized> Iterator for Box<I> type Item = I::Item;`

`fn from(s: String) -> Box<str>`

[src]

Performs the conversion.

###

`impl<T> From<Box<[T]>> for Vec<T>`

1.18.0
[src]

####

`fn from(s: Box<[T]>) -> Vec<T>`

[src]

Performs the conversion.

###

`impl<T> From<Vec<T>> for Box<[T]>`

1.20.0
[src]

####
ⓘImportant traits for Box<I>

### Important traits for Box<I>

`impl<I: Iterator + ?Sized> Iterator for Box<I> type Item = I::Item;`

`fn from(v: Vec<T>) -> Box<[T]>`

[src]

Performs the conversion.

## Auto Trait Implementations

###

`impl<T: ?Sized> Send for Box<T> where T: Send,`

###

`impl<T: ?Sized> Sync for Box<T> where T: Sync,`

## Blanket Implementations

###

`impl<A, F> FnBox for F where F: FnOnce<A>,`

[src]

#### `type Output = <F as FnOnce<A>>::Output`

🔬 This is a nightly-only experimental API. (`fnbox` #28796)

will be deprecated if and when `Box<FnOnce>` becomes usable

####

`fn call_box(Box<F>, A) -> <F as FnOnce<A>>::Output`

[src]

🔬 This is a nightly-only experimental API. (`fnbox` #28796)

will be deprecated if and when `Box<FnOnce>` becomes usable

###

`impl<T> ToOwned for T where T: Clone,`

[src]

#### `type Owned = T`

####

`fn to_owned(&Self) -> T`

[src]

Creates owned data from borrowed data, usually by cloning. Read more

####

`fn clone_into(&Self, &mut T)`

[src]

🔬 This is a nightly-only experimental API. (`toowned_clone_into` #41263)

recently added

Uses borrowed data to replace owned data, usually by cloning. Read more

###

`impl<T> ToString for T where T: Display + ?Sized,`

[src]

####

`fn to_string(&Self) -> String`

[src]

Converts the given value to a `String`. Read more

###

`impl<T, U> TryFrom for T where T: From<U>,`

[src]

#### `type Error = !`

🔬 This is a nightly-only experimental API. (`try_from` #33417)

The type returned in the event of a conversion error.

####

`fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>`

[src]

🔬 This is a nightly-only experimental API. (`try_from` #33417)

Performs the conversion.

###

`impl<T> From for T`

[src]

####

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

[src]

Performs the conversion.

###

`impl<I> IntoIterator for I where I: Iterator,`

[src]

#### `type Item = <I as Iterator>::Item`

The type of the elements being iterated over.

#### `type IntoIter = I`

Which kind of iterator are we turning this into?

####

`fn into_iter(self) -> I`

[src]

Creates an iterator from a value. Read more

###

`impl<T, U> TryInto for T where U: TryFrom<T>,`

[src]

#### `type Error = <U as TryFrom<T>>::Error`

🔬 This is a nightly-only experimental API. (`try_from` #33417)

The type returned in the event of a conversion error.

####

`fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>`

[src]

🔬 This is a nightly-only experimental API. (`try_from` #33417)

Performs the conversion.

###

`impl<T, U> Into for T where U: From<T>,`

[src]

####

`fn into(self) -> U`

[src]

Performs the conversion.

###

`impl<T> Borrow for T where T: ?Sized,`

[src]

####

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

[src]

Immutably borrows from an owned value. Read more

###

`impl<T> BorrowMut for T where T: ?Sized,`

[src]

####

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

[src]

Mutably borrows from an owned value. Read more

###

`impl<T> Any for T where T: 'static + ?Sized,`

[src]

####

`fn get_type_id(&self) -> TypeId`

[src]

🔬 This is a nightly-only experimental API. (`get_type_id` #27745)

this method will likely be replaced by an associated static

Gets the `TypeId` of `self`. Read more

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