Expand description
A pointer type for heap allocation.
See the module-level documentation for more.
Implementations
sourceimpl<T> Box<T>
impl<T> Box<T>
sourcepub fn new_uninit() -> Box<MaybeUninit<T>>ⓘNotable traits for Box<I, A>impl<I: Iterator + ?Sized, A: Allocator> Iterator for Box<I, A> type Item = I::Item;impl<F: ?Sized + Future + Unpin, A: Allocator> Future for Box<F, A>where
A: 'static, type Output = F::Output;
🔬This is a nightly-only experimental API. (new_uninit
#63291)
pub fn new_uninit() -> Box<MaybeUninit<T>>ⓘNotable traits for Box<I, A>impl<I: Iterator + ?Sized, A: Allocator> Iterator for Box<I, A> type Item = I::Item;impl<F: ?Sized + Future + Unpin, A: Allocator> Future for Box<F, A>where
A: 'static, type Output = F::Output;
A: 'static, type Output = F::Output;
new_uninit
#63291)sourcepub fn new_zeroed() -> Box<MaybeUninit<T>>ⓘNotable traits for Box<I, A>impl<I: Iterator + ?Sized, A: Allocator> Iterator for Box<I, A> type Item = I::Item;impl<F: ?Sized + Future + Unpin, A: Allocator> Future for Box<F, A>where
A: 'static, type Output = F::Output;
🔬This is a nightly-only experimental API. (new_uninit
#63291)
pub fn new_zeroed() -> Box<MaybeUninit<T>>ⓘNotable traits for Box<I, A>impl<I: Iterator + ?Sized, A: Allocator> Iterator for Box<I, A> type Item = I::Item;impl<F: ?Sized + Future + Unpin, A: Allocator> Future for Box<F, A>where
A: 'static, type Output = F::Output;
A: 'static, type Output = F::Output;
new_uninit
#63291)Constructs a new Box
with uninitialized contents, with the memory
being filled with 0
bytes.
See MaybeUninit::zeroed
for examples of correct and incorrect usage
of this method.
Examples
#![feature(new_uninit)]
let zero = Box::<u32>::new_zeroed();
let zero = unsafe { zero.assume_init() };
assert_eq!(*zero, 0)
Run1.33.0 · sourcepub fn pin(x: T) -> Pin<Box<T>>
pub fn pin(x: T) -> Pin<Box<T>>
Constructs a new Pin<Box<T>>
. If T
does not implement Unpin
, then
x
will be pinned in memory and unable to be moved.
Constructing and pinning of the Box
can also be done in two steps: Box::pin(x)
does the same as Box::into_pin(Box::new(x))
. Consider using
into_pin
if you already have a Box<T>
, or if you want to
construct a (pinned) Box
in a different way than with Box::new
.
sourcepub fn try_new(x: T) -> Result<Self, AllocError>
🔬This is a nightly-only experimental API. (allocator_api
#32838)
pub fn try_new(x: T) -> Result<Self, AllocError>
allocator_api
#32838)sourcepub fn try_new_uninit() -> Result<Box<MaybeUninit<T>>, AllocError>
🔬This is a nightly-only experimental API. (allocator_api
#32838)
pub fn try_new_uninit() -> Result<Box<MaybeUninit<T>>, AllocError>
allocator_api
#32838)Constructs a new box with uninitialized contents on the heap, returning an error if the allocation fails
Examples
#![feature(allocator_api, new_uninit)]
let mut five = Box::<u32>::try_new_uninit()?;
let five = unsafe {
// Deferred initialization:
five.as_mut_ptr().write(5);
five.assume_init()
};
assert_eq!(*five, 5);
Runsourcepub fn try_new_zeroed() -> Result<Box<MaybeUninit<T>>, AllocError>
🔬This is a nightly-only experimental API. (allocator_api
#32838)
pub fn try_new_zeroed() -> Result<Box<MaybeUninit<T>>, AllocError>
allocator_api
#32838)Constructs a new Box
with uninitialized contents, with the memory
being filled with 0
bytes on the heap
See MaybeUninit::zeroed
for examples of correct and incorrect usage
of this method.
Examples
#![feature(allocator_api, new_uninit)]
let zero = Box::<u32>::try_new_zeroed()?;
let zero = unsafe { zero.assume_init() };
assert_eq!(*zero, 0);
Runsourceimpl<T, A: Allocator> Box<T, A>
impl<T, A: Allocator> Box<T, A>
const: unstable · sourcepub fn new_in(x: T, alloc: A) -> Selfwhere
A: Allocator,
🔬This is a nightly-only experimental API. (allocator_api
#32838)
pub fn new_in(x: T, alloc: A) -> Selfwhere
A: Allocator,
allocator_api
#32838)const: unstable · sourcepub fn try_new_in(x: T, alloc: A) -> Result<Self, AllocError>where
A: Allocator,
🔬This is a nightly-only experimental API. (allocator_api
#32838)
pub fn try_new_in(x: T, alloc: A) -> Result<Self, AllocError>where
A: Allocator,
allocator_api
#32838)const: unstable · sourcepub fn new_uninit_in(alloc: A) -> Box<MaybeUninit<T>, A>ⓘNotable traits for Box<I, A>impl<I: Iterator + ?Sized, A: Allocator> Iterator for Box<I, A> type Item = I::Item;impl<F: ?Sized + Future + Unpin, A: Allocator> Future for Box<F, A>where
A: 'static, type Output = F::Output;
where
A: Allocator,
🔬This is a nightly-only experimental API. (allocator_api
#32838)
pub fn new_uninit_in(alloc: A) -> Box<MaybeUninit<T>, A>ⓘNotable traits for Box<I, A>impl<I: Iterator + ?Sized, A: Allocator> Iterator for Box<I, A> type Item = I::Item;impl<F: ?Sized + Future + Unpin, A: Allocator> Future for Box<F, A>where
A: 'static, type Output = F::Output;
where
A: Allocator,
A: 'static, type Output = F::Output;
allocator_api
#32838)Constructs a new box with uninitialized contents in the provided allocator.
Examples
#![feature(allocator_api, new_uninit)]
use std::alloc::System;
let mut five = Box::<u32, _>::new_uninit_in(System);
let five = unsafe {
// Deferred initialization:
five.as_mut_ptr().write(5);
five.assume_init()
};
assert_eq!(*five, 5)
Runconst: unstable · sourcepub fn try_new_uninit_in(alloc: A) -> Result<Box<MaybeUninit<T>, A>, AllocError>where
A: Allocator,
🔬This is a nightly-only experimental API. (allocator_api
#32838)
pub fn try_new_uninit_in(alloc: A) -> Result<Box<MaybeUninit<T>, A>, AllocError>where
A: Allocator,
allocator_api
#32838)Constructs a new box with uninitialized contents in the provided allocator, returning an error if the allocation fails
Examples
#![feature(allocator_api, new_uninit)]
use std::alloc::System;
let mut five = Box::<u32, _>::try_new_uninit_in(System)?;
let five = unsafe {
// Deferred initialization:
five.as_mut_ptr().write(5);
five.assume_init()
};
assert_eq!(*five, 5);
Runconst: unstable · sourcepub fn new_zeroed_in(alloc: A) -> Box<MaybeUninit<T>, A>ⓘNotable traits for Box<I, A>impl<I: Iterator + ?Sized, A: Allocator> Iterator for Box<I, A> type Item = I::Item;impl<F: ?Sized + Future + Unpin, A: Allocator> Future for Box<F, A>where
A: 'static, type Output = F::Output;
where
A: Allocator,
🔬This is a nightly-only experimental API. (allocator_api
#32838)
pub fn new_zeroed_in(alloc: A) -> Box<MaybeUninit<T>, A>ⓘNotable traits for Box<I, A>impl<I: Iterator + ?Sized, A: Allocator> Iterator for Box<I, A> type Item = I::Item;impl<F: ?Sized + Future + Unpin, A: Allocator> Future for Box<F, A>where
A: 'static, type Output = F::Output;
where
A: Allocator,
A: 'static, type Output = F::Output;
allocator_api
#32838)Constructs a new Box
with uninitialized contents, with the memory
being filled with 0
bytes in the provided allocator.
See MaybeUninit::zeroed
for examples of correct and incorrect usage
of this method.
Examples
#![feature(allocator_api, new_uninit)]
use std::alloc::System;
let zero = Box::<u32, _>::new_zeroed_in(System);
let zero = unsafe { zero.assume_init() };
assert_eq!(*zero, 0)
Runconst: unstable · sourcepub fn try_new_zeroed_in(alloc: A) -> Result<Box<MaybeUninit<T>, A>, AllocError>where
A: Allocator,
🔬This is a nightly-only experimental API. (allocator_api
#32838)
pub fn try_new_zeroed_in(alloc: A) -> Result<Box<MaybeUninit<T>, A>, AllocError>where
A: Allocator,
allocator_api
#32838)Constructs a new Box
with uninitialized contents, with the memory
being filled with 0
bytes in the provided allocator,
returning an error if the allocation fails,
See MaybeUninit::zeroed
for examples of correct and incorrect usage
of this method.
Examples
#![feature(allocator_api, new_uninit)]
use std::alloc::System;
let zero = Box::<u32, _>::try_new_zeroed_in(System)?;
let zero = unsafe { zero.assume_init() };
assert_eq!(*zero, 0);
Runconst: unstable · sourcepub fn pin_in(x: T, alloc: A) -> Pin<Self>where
A: 'static + Allocator,
🔬This is a nightly-only experimental API. (allocator_api
#32838)
pub fn pin_in(x: T, alloc: A) -> Pin<Self>where
A: 'static + Allocator,
allocator_api
#32838)Constructs a new Pin<Box<T, A>>
. If T
does not implement Unpin
, then
x
will be pinned in memory and unable to be moved.
Constructing and pinning of the Box
can also be done in two steps: Box::pin_in(x, alloc)
does the same as Box::into_pin(Box::new_in(x, alloc))
. Consider using
into_pin
if you already have a Box<T, A>
, or if you want to
construct a (pinned) Box
in a different way than with Box::new_in
.
const: unstable · sourcepub fn into_boxed_slice(boxed: Self) -> Box<[T], A>ⓘNotable traits for Box<I, A>impl<I: Iterator + ?Sized, A: Allocator> Iterator for Box<I, A> type Item = I::Item;impl<F: ?Sized + Future + Unpin, A: Allocator> Future for Box<F, A>where
A: 'static, type Output = F::Output;
🔬This is a nightly-only experimental API. (box_into_boxed_slice
#71582)
pub fn into_boxed_slice(boxed: Self) -> Box<[T], A>ⓘNotable traits for Box<I, A>impl<I: Iterator + ?Sized, A: Allocator> Iterator for Box<I, A> type Item = I::Item;impl<F: ?Sized + Future + Unpin, A: Allocator> Future for Box<F, A>where
A: 'static, type Output = F::Output;
A: 'static, type Output = F::Output;
box_into_boxed_slice
#71582)Converts a Box<T>
into a Box<[T]>
This conversion does not allocate on the heap and happens in place.
sourceimpl<T> Box<[T]>
impl<T> Box<[T]>
sourcepub fn new_uninit_slice(len: usize) -> Box<[MaybeUninit<T>]>ⓘNotable traits for Box<I, A>impl<I: Iterator + ?Sized, A: Allocator> Iterator for Box<I, A> type Item = I::Item;impl<F: ?Sized + Future + Unpin, A: Allocator> Future for Box<F, A>where
A: 'static, type Output = F::Output;
🔬This is a nightly-only experimental API. (new_uninit
#63291)
pub fn new_uninit_slice(len: usize) -> Box<[MaybeUninit<T>]>ⓘNotable traits for Box<I, A>impl<I: Iterator + ?Sized, A: Allocator> Iterator for Box<I, A> type Item = I::Item;impl<F: ?Sized + Future + Unpin, A: Allocator> Future for Box<F, A>where
A: 'static, type Output = F::Output;
A: 'static, type Output = F::Output;
new_uninit
#63291)Constructs a new boxed slice with uninitialized contents.
Examples
#![feature(new_uninit)]
let mut values = Box::<[u32]>::new_uninit_slice(3);
let values = unsafe {
// Deferred initialization:
values[0].as_mut_ptr().write(1);
values[1].as_mut_ptr().write(2);
values[2].as_mut_ptr().write(3);
values.assume_init()
};
assert_eq!(*values, [1, 2, 3])
Runsourcepub fn new_zeroed_slice(len: usize) -> Box<[MaybeUninit<T>]>ⓘNotable traits for Box<I, A>impl<I: Iterator + ?Sized, A: Allocator> Iterator for Box<I, A> type Item = I::Item;impl<F: ?Sized + Future + Unpin, A: Allocator> Future for Box<F, A>where
A: 'static, type Output = F::Output;
🔬This is a nightly-only experimental API. (new_uninit
#63291)
pub fn new_zeroed_slice(len: usize) -> Box<[MaybeUninit<T>]>ⓘNotable traits for Box<I, A>impl<I: Iterator + ?Sized, A: Allocator> Iterator for Box<I, A> type Item = I::Item;impl<F: ?Sized + Future + Unpin, A: Allocator> Future for Box<F, A>where
A: 'static, type Output = F::Output;
A: 'static, type Output = F::Output;
new_uninit
#63291)Constructs a new boxed slice with uninitialized contents, with the memory
being filled with 0
bytes.
See MaybeUninit::zeroed
for examples of correct and incorrect usage
of this method.
Examples
#![feature(new_uninit)]
let values = Box::<[u32]>::new_zeroed_slice(3);
let values = unsafe { values.assume_init() };
assert_eq!(*values, [0, 0, 0])
Runsourcepub fn try_new_uninit_slice(
len: usize
) -> Result<Box<[MaybeUninit<T>]>, AllocError>
🔬This is a nightly-only experimental API. (allocator_api
#32838)
pub fn try_new_uninit_slice(
len: usize
) -> Result<Box<[MaybeUninit<T>]>, AllocError>
allocator_api
#32838)Constructs a new boxed slice with uninitialized contents. Returns an error if the allocation fails
Examples
#![feature(allocator_api, new_uninit)]
let mut values = Box::<[u32]>::try_new_uninit_slice(3)?;
let values = unsafe {
// Deferred initialization:
values[0].as_mut_ptr().write(1);
values[1].as_mut_ptr().write(2);
values[2].as_mut_ptr().write(3);
values.assume_init()
};
assert_eq!(*values, [1, 2, 3]);
Runsourcepub fn try_new_zeroed_slice(
len: usize
) -> Result<Box<[MaybeUninit<T>]>, AllocError>
🔬This is a nightly-only experimental API. (allocator_api
#32838)
pub fn try_new_zeroed_slice(
len: usize
) -> Result<Box<[MaybeUninit<T>]>, AllocError>
allocator_api
#32838)Constructs a new boxed slice with uninitialized contents, with the memory
being filled with 0
bytes. Returns an error if the allocation fails
See MaybeUninit::zeroed
for examples of correct and incorrect usage
of this method.
Examples
#![feature(allocator_api, new_uninit)]
let values = Box::<[u32]>::try_new_zeroed_slice(3)?;
let values = unsafe { values.assume_init() };
assert_eq!(*values, [0, 0, 0]);
Runsourceimpl<T, A: Allocator> Box<[T], A>
impl<T, A: Allocator> Box<[T], A>
sourcepub fn new_uninit_slice_in(len: usize, alloc: A) -> Box<[MaybeUninit<T>], A>ⓘNotable traits for Box<I, A>impl<I: Iterator + ?Sized, A: Allocator> Iterator for Box<I, A> type Item = I::Item;impl<F: ?Sized + Future + Unpin, A: Allocator> Future for Box<F, A>where
A: 'static, type Output = F::Output;
🔬This is a nightly-only experimental API. (allocator_api
#32838)
pub fn new_uninit_slice_in(len: usize, alloc: A) -> Box<[MaybeUninit<T>], A>ⓘNotable traits for Box<I, A>impl<I: Iterator + ?Sized, A: Allocator> Iterator for Box<I, A> type Item = I::Item;impl<F: ?Sized + Future + Unpin, A: Allocator> Future for Box<F, A>where
A: 'static, type Output = F::Output;
A: 'static, type Output = F::Output;
allocator_api
#32838)Constructs a new boxed slice with uninitialized contents in the provided allocator.
Examples
#![feature(allocator_api, new_uninit)]
use std::alloc::System;
let mut values = Box::<[u32], _>::new_uninit_slice_in(3, System);
let values = unsafe {
// Deferred initialization:
values[0].as_mut_ptr().write(1);
values[1].as_mut_ptr().write(2);
values[2].as_mut_ptr().write(3);
values.assume_init()
};
assert_eq!(*values, [1, 2, 3])
Runsourcepub fn new_zeroed_slice_in(len: usize, alloc: A) -> Box<[MaybeUninit<T>], A>ⓘNotable traits for Box<I, A>impl<I: Iterator + ?Sized, A: Allocator> Iterator for Box<I, A> type Item = I::Item;impl<F: ?Sized + Future + Unpin, A: Allocator> Future for Box<F, A>where
A: 'static, type Output = F::Output;
🔬This is a nightly-only experimental API. (allocator_api
#32838)
pub fn new_zeroed_slice_in(len: usize, alloc: A) -> Box<[MaybeUninit<T>], A>ⓘNotable traits for Box<I, A>impl<I: Iterator + ?Sized, A: Allocator> Iterator for Box<I, A> type Item = I::Item;impl<F: ?Sized + Future + Unpin, A: Allocator> Future for Box<F, A>where
A: 'static, type Output = F::Output;
A: 'static, type Output = F::Output;
allocator_api
#32838)Constructs a new boxed slice with uninitialized contents in the provided allocator,
with the memory being filled with 0
bytes.
See MaybeUninit::zeroed
for examples of correct and incorrect usage
of this method.
Examples
#![feature(allocator_api, new_uninit)]
use std::alloc::System;
let values = Box::<[u32], _>::new_zeroed_slice_in(3, System);
let values = unsafe { values.assume_init() };
assert_eq!(*values, [0, 0, 0])
Runsourceimpl<T, A: Allocator> Box<MaybeUninit<T>, A>
impl<T, A: Allocator> Box<MaybeUninit<T>, A>
const: unstable · sourcepub unsafe fn assume_init(self) -> Box<T, A>ⓘNotable traits for Box<I, A>impl<I: Iterator + ?Sized, A: Allocator> Iterator for Box<I, A> type Item = I::Item;impl<F: ?Sized + Future + Unpin, A: Allocator> Future for Box<F, A>where
A: 'static, type Output = F::Output;
🔬This is a nightly-only experimental API. (new_uninit
#63291)
pub unsafe fn assume_init(self) -> Box<T, A>ⓘNotable traits for Box<I, A>impl<I: Iterator + ?Sized, A: Allocator> Iterator for Box<I, A> type Item = I::Item;impl<F: ?Sized + Future + Unpin, A: Allocator> Future for Box<F, A>where
A: 'static, type Output = F::Output;
A: 'static, type Output = F::Output;
new_uninit
#63291)Converts to Box<T, A>
.
Safety
As with MaybeUninit::assume_init
,
it is up to the caller to guarantee that the value
really is in an initialized state.
Calling this when the content is not yet fully initialized
causes immediate undefined behavior.
Examples
#![feature(new_uninit)]
let mut five = Box::<u32>::new_uninit();
let five: Box<u32> = unsafe {
// Deferred initialization:
five.as_mut_ptr().write(5);
five.assume_init()
};
assert_eq!(*five, 5)
Runconst: unstable · sourcepub fn write(boxed: Self, value: T) -> Box<T, A>ⓘNotable traits for Box<I, A>impl<I: Iterator + ?Sized, A: Allocator> Iterator for Box<I, A> type Item = I::Item;impl<F: ?Sized + Future + Unpin, A: Allocator> Future for Box<F, A>where
A: 'static, type Output = F::Output;
🔬This is a nightly-only experimental API. (new_uninit
#63291)
pub fn write(boxed: Self, value: T) -> Box<T, A>ⓘNotable traits for Box<I, A>impl<I: Iterator + ?Sized, A: Allocator> Iterator for Box<I, A> type Item = I::Item;impl<F: ?Sized + Future + Unpin, A: Allocator> Future for Box<F, A>where
A: 'static, type Output = F::Output;
A: 'static, type Output = F::Output;
new_uninit
#63291)Writes the value and converts to Box<T, A>
.
This method converts the box similarly to Box::assume_init
but
writes value
into it before conversion thus guaranteeing safety.
In some scenarios use of this method may improve performance because
the compiler may be able to optimize copying from stack.
Examples
#![feature(new_uninit)]
let big_box = Box::<[usize; 1024]>::new_uninit();
let mut array = [0; 1024];
for (i, place) in array.iter_mut().enumerate() {
*place = i;
}
// The optimizer may be able to elide this copy, so previous code writes
// to heap directly.
let big_box = Box::write(big_box, array);
for (i, x) in big_box.iter().enumerate() {
assert_eq!(*x, i);
}
Runsourceimpl<T, A: Allocator> Box<[MaybeUninit<T>], A>
impl<T, A: Allocator> Box<[MaybeUninit<T>], A>
sourcepub unsafe fn assume_init(self) -> Box<[T], A>ⓘNotable traits for Box<I, A>impl<I: Iterator + ?Sized, A: Allocator> Iterator for Box<I, A> type Item = I::Item;impl<F: ?Sized + Future + Unpin, A: Allocator> Future for Box<F, A>where
A: 'static, type Output = F::Output;
🔬This is a nightly-only experimental API. (new_uninit
#63291)
pub unsafe fn assume_init(self) -> Box<[T], A>ⓘNotable traits for Box<I, A>impl<I: Iterator + ?Sized, A: Allocator> Iterator for Box<I, A> type Item = I::Item;impl<F: ?Sized + Future + Unpin, A: Allocator> Future for Box<F, A>where
A: 'static, type Output = F::Output;
A: 'static, type Output = F::Output;
new_uninit
#63291)Converts to Box<[T], A>
.
Safety
As with MaybeUninit::assume_init
,
it is up to the caller to guarantee that the values
really are in an initialized state.
Calling this when the content is not yet fully initialized
causes immediate undefined behavior.
Examples
#![feature(new_uninit)]
let mut values = Box::<[u32]>::new_uninit_slice(3);
let values = unsafe {
// Deferred initialization:
values[0].as_mut_ptr().write(1);
values[1].as_mut_ptr().write(2);
values[2].as_mut_ptr().write(3);
values.assume_init()
};
assert_eq!(*values, [1, 2, 3])
Runsourceimpl<T: ?Sized> Box<T>
impl<T: ?Sized> Box<T>
1.4.0 · sourcepub unsafe fn from_raw(raw: *mut T) -> Self
pub unsafe fn from_raw(raw: *mut T) -> Self
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. For this
to be safe, the memory must have been allocated in accordance
with the memory layout used by Box
.
Safety
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.
The safety conditions are described in the memory layout section.
Examples
Recreate a Box
which was previously converted to a raw pointer
using Box::into_raw
:
let x = Box::new(5);
let ptr = Box::into_raw(x);
let x = unsafe { Box::from_raw(ptr) };
RunManually create a Box
from scratch by using the global allocator:
use std::alloc::{alloc, Layout};
unsafe {
let ptr = alloc(Layout::new::<i32>()) as *mut i32;
// In general .write is required to avoid attempting to destruct
// the (uninitialized) previous contents of `ptr`, though for this
// simple example `*ptr = 5` would have worked as well.
ptr.write(5);
let x = Box::from_raw(ptr);
}
Runsourceimpl<T: ?Sized, A: Allocator> Box<T, A>
impl<T: ?Sized, A: Allocator> Box<T, A>
const: unstable · sourcepub unsafe fn from_raw_in(raw: *mut T, alloc: A) -> Self
🔬This is a nightly-only experimental API. (allocator_api
#32838)
pub unsafe fn from_raw_in(raw: *mut T, alloc: A) -> Self
allocator_api
#32838)Constructs a box from a raw pointer in the given allocator.
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. For this
to be safe, the memory must have been allocated in accordance
with the memory layout used by Box
.
Safety
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
Recreate a Box
which was previously converted to a raw pointer
using Box::into_raw_with_allocator
:
#![feature(allocator_api)]
use std::alloc::System;
let x = Box::new_in(5, System);
let (ptr, alloc) = Box::into_raw_with_allocator(x);
let x = unsafe { Box::from_raw_in(ptr, alloc) };
RunManually create a Box
from scratch by using the system allocator:
#![feature(allocator_api, slice_ptr_get)]
use std::alloc::{Allocator, Layout, System};
unsafe {
let ptr = System.allocate(Layout::new::<i32>())?.as_mut_ptr() as *mut i32;
// In general .write is required to avoid attempting to destruct
// the (uninitialized) previous contents of `ptr`, though for this
// simple example `*ptr = 5` would have worked as well.
ptr.write(5);
let x = Box::from_raw_in(ptr, System);
}
Run1.4.0 · sourcepub fn into_raw(b: Self) -> *mut T
pub fn into_raw(b: Self) -> *mut T
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, taking
into account the memory layout used by Box
. The easiest way to
do this is to convert the raw pointer back into a Box
with the
Box::from_raw
function, allowing the Box
destructor to perform
the cleanup.
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
Converting the raw pointer back into a Box
with Box::from_raw
for automatic cleanup:
let x = Box::new(String::from("Hello"));
let ptr = Box::into_raw(x);
let x = unsafe { Box::from_raw(ptr) };
RunManual cleanup by explicitly running the destructor and deallocating the memory:
use std::alloc::{dealloc, Layout};
use std::ptr;
let x = Box::new(String::from("Hello"));
let p = Box::into_raw(x);
unsafe {
ptr::drop_in_place(p);
dealloc(p as *mut u8, Layout::new::<String>());
}
Runconst: unstable · sourcepub fn into_raw_with_allocator(b: Self) -> (*mut T, A)
🔬This is a nightly-only experimental API. (allocator_api
#32838)
pub fn into_raw_with_allocator(b: Self) -> (*mut T, A)
allocator_api
#32838)Consumes the Box
, returning a wrapped raw pointer and the allocator.
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, taking
into account the memory layout used by Box
. The easiest way to
do this is to convert the raw pointer back into a Box
with the
Box::from_raw_in
function, allowing the Box
destructor to perform
the cleanup.
Note: this is an associated function, which means that you have
to call it as Box::into_raw_with_allocator(b)
instead of b.into_raw_with_allocator()
. This
is so that there is no conflict with a method on the inner type.
Examples
Converting the raw pointer back into a Box
with Box::from_raw_in
for automatic cleanup:
#![feature(allocator_api)]
use std::alloc::System;
let x = Box::new_in(String::from("Hello"), System);
let (ptr, alloc) = Box::into_raw_with_allocator(x);
let x = unsafe { Box::from_raw_in(ptr, alloc) };
RunManual cleanup by explicitly running the destructor and deallocating the memory:
#![feature(allocator_api)]
use std::alloc::{Allocator, Layout, System};
use std::ptr::{self, NonNull};
let x = Box::new_in(String::from("Hello"), System);
let (ptr, alloc) = Box::into_raw_with_allocator(x);
unsafe {
ptr::drop_in_place(ptr);
let non_null = NonNull::new_unchecked(ptr);
alloc.deallocate(non_null.cast(), Layout::new::<String>());
}
Runconst: unstable · sourcepub fn allocator(b: &Self) -> &A
🔬This is a nightly-only experimental API. (allocator_api
#32838)
pub fn allocator(b: &Self) -> &A
allocator_api
#32838)Returns a reference to the underlying allocator.
Note: this is an associated function, which means that you have
to call it as Box::allocator(&b)
instead of b.allocator()
. This
is so that there is no conflict with a method on the inner type.
1.26.0 (const: unstable) · sourcepub fn leak<'a>(b: Self) -> &'a mut Twhere
A: 'a,
pub fn leak<'a>(b: Self) -> &'a mut Twhere
A: 'a,
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:
let x = Box::new(41);
let static_ref: &'static mut usize = Box::leak(x);
*static_ref += 1;
assert_eq!(*static_ref, 42);
RunUnsized data:
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]);
Run1.63.0 (const: unstable) · sourcepub fn into_pin(boxed: Self) -> Pin<Self>where
A: 'static,
pub fn into_pin(boxed: Self) -> Pin<Self>where
A: 'static,
Converts a Box<T>
into a Pin<Box<T>>
. If T
does not implement Unpin
, then
*boxed
will be pinned in memory and unable to be moved.
This conversion does not allocate on the heap and happens in place.
This is also available via From
.
Constructing and pinning a Box
with Box::into_pin(Box::new(x))
can also be written more concisely using Box::pin(x)
.
This into_pin
method is useful if you already have a Box<T>
, or you are
constructing a (pinned) Box
in a different way than with Box::new
.
Notes
It’s not recommended that crates add an impl like From<Box<T>> for Pin<T>
,
as it’ll introduce an ambiguity when calling Pin::from
.
A demonstration of such a poor impl is shown below.
struct Foo; // A type defined in this crate.
impl From<Box<()>> for Pin<Foo> {
fn from(_: Box<()>) -> Pin<Foo> {
Pin::new(Foo)
}
}
let foo = Box::new(());
let bar = Pin::from(foo);
Runsourceimpl<A: Allocator> Box<dyn Any, A>
impl<A: Allocator> Box<dyn Any, A>
sourcepub fn downcast<T: Any>(self) -> Result<Box<T, A>, Self>
pub fn downcast<T: Any>(self) -> Result<Box<T, A>, Self>
Attempt to downcast the box to a concrete type.
Examples
use std::any::Any;
fn print_if_string(value: Box<dyn Any>) {
if let Ok(string) = value.downcast::<String>() {
println!("String ({}): {}", string.len(), string);
}
}
let my_string = "Hello World".to_string();
print_if_string(Box::new(my_string));
print_if_string(Box::new(0i8));
Runsourcepub unsafe fn downcast_unchecked<T: Any>(self) -> Box<T, A>ⓘNotable traits for Box<I, A>impl<I: Iterator + ?Sized, A: Allocator> Iterator for Box<I, A> type Item = I::Item;impl<F: ?Sized + Future + Unpin, A: Allocator> Future for Box<F, A>where
A: 'static, type Output = F::Output;
🔬This is a nightly-only experimental API. (downcast_unchecked
#90850)
pub unsafe fn downcast_unchecked<T: Any>(self) -> Box<T, A>ⓘNotable traits for Box<I, A>impl<I: Iterator + ?Sized, A: Allocator> Iterator for Box<I, A> type Item = I::Item;impl<F: ?Sized + Future + Unpin, A: Allocator> Future for Box<F, A>where
A: 'static, type Output = F::Output;
A: 'static, type Output = F::Output;
downcast_unchecked
#90850)Downcasts the box to a concrete type.
For a safe alternative see downcast
.
Examples
#![feature(downcast_unchecked)]
use std::any::Any;
let x: Box<dyn Any> = Box::new(1_usize);
unsafe {
assert_eq!(*x.downcast_unchecked::<usize>(), 1);
}
RunSafety
The contained value must be of type T
. Calling this method
with the incorrect type is undefined behavior.
sourceimpl<A: Allocator> Box<dyn Any + Send, A>
impl<A: Allocator> Box<dyn Any + Send, A>
sourcepub fn downcast<T: Any>(self) -> Result<Box<T, A>, Self>
pub fn downcast<T: Any>(self) -> Result<Box<T, A>, Self>
Attempt to downcast the box to a concrete type.
Examples
use std::any::Any;
fn print_if_string(value: Box<dyn Any + Send>) {
if let Ok(string) = value.downcast::<String>() {
println!("String ({}): {}", string.len(), string);
}
}
let my_string = "Hello World".to_string();
print_if_string(Box::new(my_string));
print_if_string(Box::new(0i8));
Runsourcepub unsafe fn downcast_unchecked<T: Any>(self) -> Box<T, A>ⓘNotable traits for Box<I, A>impl<I: Iterator + ?Sized, A: Allocator> Iterator for Box<I, A> type Item = I::Item;impl<F: ?Sized + Future + Unpin, A: Allocator> Future for Box<F, A>where
A: 'static, type Output = F::Output;
🔬This is a nightly-only experimental API. (downcast_unchecked
#90850)
pub unsafe fn downcast_unchecked<T: Any>(self) -> Box<T, A>ⓘNotable traits for Box<I, A>impl<I: Iterator + ?Sized, A: Allocator> Iterator for Box<I, A> type Item = I::Item;impl<F: ?Sized + Future + Unpin, A: Allocator> Future for Box<F, A>where
A: 'static, type Output = F::Output;
A: 'static, type Output = F::Output;
downcast_unchecked
#90850)Downcasts the box to a concrete type.
For a safe alternative see downcast
.
Examples
#![feature(downcast_unchecked)]
use std::any::Any;
let x: Box<dyn Any + Send> = Box::new(1_usize);
unsafe {
assert_eq!(*x.downcast_unchecked::<usize>(), 1);
}
RunSafety
The contained value must be of type T
. Calling this method
with the incorrect type is undefined behavior.
sourceimpl<A: Allocator> Box<dyn Any + Send + Sync, A>
impl<A: Allocator> Box<dyn Any + Send + Sync, A>
1.51.0 · sourcepub fn downcast<T: Any>(self) -> Result<Box<T, A>, Self>
pub fn downcast<T: Any>(self) -> Result<Box<T, A>, Self>
Attempt to downcast the box to a concrete type.
Examples
use std::any::Any;
fn print_if_string(value: Box<dyn Any + Send + Sync>) {
if let Ok(string) = value.downcast::<String>() {
println!("String ({}): {}", string.len(), string);
}
}
let my_string = "Hello World".to_string();
print_if_string(Box::new(my_string));
print_if_string(Box::new(0i8));
Runsourcepub unsafe fn downcast_unchecked<T: Any>(self) -> Box<T, A>ⓘNotable traits for Box<I, A>impl<I: Iterator + ?Sized, A: Allocator> Iterator for Box<I, A> type Item = I::Item;impl<F: ?Sized + Future + Unpin, A: Allocator> Future for Box<F, A>where
A: 'static, type Output = F::Output;
🔬This is a nightly-only experimental API. (downcast_unchecked
#90850)
pub unsafe fn downcast_unchecked<T: Any>(self) -> Box<T, A>ⓘNotable traits for Box<I, A>impl<I: Iterator + ?Sized, A: Allocator> Iterator for Box<I, A> type Item = I::Item;impl<F: ?Sized + Future + Unpin, A: Allocator> Future for Box<F, A>where
A: 'static, type Output = F::Output;
A: 'static, type Output = F::Output;
downcast_unchecked
#90850)Downcasts the box to a concrete type.
For a safe alternative see downcast
.
Examples
#![feature(downcast_unchecked)]
use std::any::Any;
let x: Box<dyn Any + Send + Sync> = Box::new(1_usize);
unsafe {
assert_eq!(*x.downcast_unchecked::<usize>(), 1);
}
RunSafety
The contained value must be of type T
. Calling this method
with the incorrect type is undefined behavior.
Trait Implementations
sourceimpl<S: ?Sized + AsyncIterator + Unpin> AsyncIterator for Box<S>
impl<S: ?Sized + AsyncIterator + Unpin> AsyncIterator for Box<S>
type Item = <S as AsyncIterator>::Item
type Item = <S as AsyncIterator>::Item
async_iterator
#79024)sourcefn poll_next(
self: Pin<&mut Self>,
cx: &mut Context<'_>
) -> Poll<Option<Self::Item>>
fn poll_next(
self: Pin<&mut Self>,
cx: &mut Context<'_>
) -> Poll<Option<Self::Item>>
async_iterator
#79024)None
if the async iterator is exhausted. Read more1.1.0 · sourceimpl<T: ?Sized, A: Allocator> BorrowMut<T> for Box<T, A>
impl<T: ?Sized, A: Allocator> BorrowMut<T> for Box<T, A>
sourcefn borrow_mut(&mut self) -> &mut T
fn borrow_mut(&mut self) -> &mut T
sourceimpl<T: Clone, A: Allocator + Clone> Clone for Box<T, A>
impl<T: Clone, A: Allocator + Clone> Clone for Box<T, A>
sourcefn clone_from(&mut self, source: &Self)
fn clone_from(&mut self, source: &Self)
1.17.0 · sourceimpl Default for Box<CStr>
impl Default for Box<CStr>
sourcefn default() -> Box<CStr>ⓘNotable traits for Box<I, A>impl<I: Iterator + ?Sized, A: Allocator> Iterator for Box<I, A> type Item = I::Item;impl<F: ?Sized + Future + Unpin, A: Allocator> Future for Box<F, A>where
A: 'static, type Output = F::Output;
fn default() -> Box<CStr>ⓘNotable traits for Box<I, A>impl<I: Iterator + ?Sized, A: Allocator> Iterator for Box<I, A> type Item = I::Item;impl<F: ?Sized + Future + Unpin, A: Allocator> Future for Box<F, A>where
A: 'static, type Output = F::Output;
A: 'static, type Output = F::Output;
sourceimpl<I: DoubleEndedIterator + ?Sized, A: Allocator> DoubleEndedIterator for Box<I, A>
impl<I: DoubleEndedIterator + ?Sized, A: Allocator> DoubleEndedIterator for Box<I, A>
sourcefn next_back(&mut self) -> Option<I::Item>
fn next_back(&mut self) -> Option<I::Item>
sourcefn nth_back(&mut self, n: usize) -> Option<I::Item>
fn nth_back(&mut self, n: usize) -> Option<I::Item>
n
th element from the end of the iterator. Read moresourcefn advance_back_by(&mut self, n: usize) -> Result<(), usize>
fn advance_back_by(&mut self, n: usize) -> Result<(), usize>
iter_advance_by
#77404)n
elements. Read more1.27.0 · sourcefn try_rfold<B, F, R>(&mut self, init: B, f: F) -> Rwhere
F: FnMut(B, Self::Item) -> R,
R: Try<Output = B>,
fn try_rfold<B, F, R>(&mut self, init: B, f: F) -> Rwhere
F: FnMut(B, Self::Item) -> R,
R: Try<Output = B>,
Iterator::try_fold()
: it takes
elements starting from the back of the iterator. Read more1.8.0 · sourceimpl<T: Error> Error for Box<T>
impl<T: Error> Error for Box<T>
sourcefn description(&self) -> &str
fn description(&self) -> &str
sourcefn cause(&self) -> Option<&dyn Error>
fn cause(&self) -> Option<&dyn Error>
sourceimpl<I: ExactSizeIterator + ?Sized, A: Allocator> ExactSizeIterator for Box<I, A>
impl<I: ExactSizeIterator + ?Sized, A: Allocator> ExactSizeIterator for Box<I, A>
1.45.0 · sourceimpl Extend<Box<str, Global>> for String
impl Extend<Box<str, Global>> for String
sourcefn extend<I: IntoIterator<Item = Box<str>>>(&mut self, iter: I)
fn extend<I: IntoIterator<Item = Box<str>>>(&mut self, iter: I)
sourcefn extend_one(&mut self, item: A)
fn extend_one(&mut self, item: A)
extend_one
#72631)sourcefn extend_reserve(&mut self, additional: usize)
fn extend_reserve(&mut self, additional: usize)
extend_one
#72631)1.17.0 · sourceimpl<T: Copy> From<&[T]> for Box<[T]>
impl<T: Copy> From<&[T]> for Box<[T]>
sourcefn from(slice: &[T]) -> Box<[T]>ⓘNotable traits for Box<I, A>impl<I: Iterator + ?Sized, A: Allocator> Iterator for Box<I, A> type Item = I::Item;impl<F: ?Sized + Future + Unpin, A: Allocator> Future for Box<F, A>where
A: 'static, type Output = F::Output;
fn from(slice: &[T]) -> Box<[T]>ⓘNotable traits for Box<I, A>impl<I: Iterator + ?Sized, A: Allocator> Iterator for Box<I, A> type Item = I::Item;impl<F: ?Sized + Future + Unpin, A: Allocator> Future for Box<F, A>where
A: 'static, type Output = F::Output;
A: 'static, type Output = F::Output;
Converts a &[T]
into a Box<[T]>
This conversion allocates on the heap
and performs a copy of slice
and its contents.
Examples
// create a &[u8] which will be used to create a Box<[u8]>
let slice: &[u8] = &[104, 101, 108, 108, 111];
let boxed_slice: Box<[u8]> = Box::from(slice);
println!("{boxed_slice:?}");
Run1.17.0 · sourceimpl From<&CStr> for Box<CStr>
impl From<&CStr> for Box<CStr>
sourcefn from(s: &CStr) -> Box<CStr>ⓘNotable traits for Box<I, A>impl<I: Iterator + ?Sized, A: Allocator> Iterator for Box<I, A> type Item = I::Item;impl<F: ?Sized + Future + Unpin, A: Allocator> Future for Box<F, A>where
A: 'static, type Output = F::Output;
fn from(s: &CStr) -> Box<CStr>ⓘNotable traits for Box<I, A>impl<I: Iterator + ?Sized, A: Allocator> Iterator for Box<I, A> type Item = I::Item;impl<F: ?Sized + Future + Unpin, A: Allocator> Future for Box<F, A>where
A: 'static, type Output = F::Output;
A: 'static, type Output = F::Output;
Converts a &CStr
into a Box<CStr>
,
by copying the contents into a newly allocated Box
.
sourceimpl<'a> From<&str> for Box<dyn Error + Send + Sync + 'a>
impl<'a> From<&str> for Box<dyn Error + Send + Sync + 'a>
1.6.0 · sourceimpl From<&str> for Box<dyn Error>
impl From<&str> for Box<dyn Error>
1.17.0 · sourceimpl From<&str> for Box<str>
impl From<&str> for Box<str>
1.45.0 · sourceimpl<T, const N: usize> From<[T; N]> for Box<[T]>
impl<T, const N: usize> From<[T; N]> for Box<[T]>
1.33.0 (const: unstable) · sourceimpl<T: ?Sized, A: Allocator> From<Box<T, A>> for Pin<Box<T, A>>where
A: 'static,
impl<T: ?Sized, A: Allocator> From<Box<T, A>> for Pin<Box<T, A>>where
A: 'static,
const: unstable · sourcefn from(boxed: Box<T, A>) -> Self
fn from(boxed: Box<T, A>) -> Self
Converts a Box<T>
into a Pin<Box<T>>
. If T
does not implement Unpin
, then
*boxed
will be pinned in memory and unable to be moved.
This conversion does not allocate on the heap and happens in place.
This is also available via Box::into_pin
.
Constructing and pinning a Box
with <Pin<Box<T>>>::from(Box::new(x))
can also be written more concisely using Box::pin(x)
.
This From
implementation is useful if you already have a Box<T>
, or you are
constructing a (pinned) Box
in a different way than with Box::new
.
1.19.0 · sourceimpl<A: Allocator> From<Box<str, A>> for Box<[u8], A>
impl<A: Allocator> From<Box<str, A>> for Box<[u8], A>
sourcefn from(s: Box<str, A>) -> Self
fn from(s: Box<str, A>) -> Self
Converts a Box<str>
into a Box<[u8]>
This conversion does not allocate on the heap and happens in place.
Examples
// create a Box<str> which will be used to create a Box<[u8]>
let boxed: Box<str> = Box::from("hello");
let boxed_str: Box<[u8]> = Box::from(boxed);
// create a &[u8] which will be used to create a Box<[u8]>
let slice: &[u8] = &[104, 101, 108, 108, 111];
let boxed_slice = Box::from(slice);
assert_eq!(boxed_slice, boxed_str);
Run1.20.0 · sourceimpl From<CString> for Box<CStr>
impl From<CString> for Box<CStr>
1.45.0 · sourceimpl<T: Copy> From<Cow<'_, [T]>> for Box<[T]>
impl<T: Copy> From<Cow<'_, [T]>> for Box<[T]>
sourcefn from(cow: Cow<'_, [T]>) -> Box<[T]>ⓘNotable traits for Box<I, A>impl<I: Iterator + ?Sized, A: Allocator> Iterator for Box<I, A> type Item = I::Item;impl<F: ?Sized + Future + Unpin, A: Allocator> Future for Box<F, A>where
A: 'static, type Output = F::Output;
fn from(cow: Cow<'_, [T]>) -> Box<[T]>ⓘNotable traits for Box<I, A>impl<I: Iterator + ?Sized, A: Allocator> Iterator for Box<I, A> type Item = I::Item;impl<F: ?Sized + Future + Unpin, A: Allocator> Future for Box<F, A>where
A: 'static, type Output = F::Output;
A: 'static, type Output = F::Output;
Converts a Cow<'_, [T]>
into a Box<[T]>
When cow
is the Cow::Borrowed
variant, this
conversion allocates on the heap and copies the
underlying slice. Otherwise, it will try to reuse the owned
Vec
’s allocation.
1.45.0 · sourceimpl From<Cow<'_, CStr>> for Box<CStr>
impl From<Cow<'_, CStr>> for Box<CStr>
sourcefn from(cow: Cow<'_, CStr>) -> Box<CStr>ⓘNotable traits for Box<I, A>impl<I: Iterator + ?Sized, A: Allocator> Iterator for Box<I, A> type Item = I::Item;impl<F: ?Sized + Future + Unpin, A: Allocator> Future for Box<F, A>where
A: 'static, type Output = F::Output;
fn from(cow: Cow<'_, CStr>) -> Box<CStr>ⓘNotable traits for Box<I, A>impl<I: Iterator + ?Sized, A: Allocator> Iterator for Box<I, A> type Item = I::Item;impl<F: ?Sized + Future + Unpin, A: Allocator> Future for Box<F, A>where
A: 'static, type Output = F::Output;
A: 'static, type Output = F::Output;
Converts a Cow<'a, CStr>
into a Box<CStr>
,
by copying the contents if they are borrowed.
1.45.0 · sourceimpl From<Cow<'_, str>> for Box<str>
impl From<Cow<'_, str>> for Box<str>
sourcefn from(cow: Cow<'_, str>) -> Box<str>ⓘNotable traits for Box<I, A>impl<I: Iterator + ?Sized, A: Allocator> Iterator for Box<I, A> type Item = I::Item;impl<F: ?Sized + Future + Unpin, A: Allocator> Future for Box<F, A>where
A: 'static, type Output = F::Output;
fn from(cow: Cow<'_, str>) -> Box<str>ⓘNotable traits for Box<I, A>impl<I: Iterator + ?Sized, A: Allocator> Iterator for Box<I, A> type Item = I::Item;impl<F: ?Sized + Future + Unpin, A: Allocator> Future for Box<F, A>where
A: 'static, type Output = F::Output;
A: 'static, type Output = F::Output;
Converts a Cow<'_, str>
into a Box<str>
When cow
is the Cow::Borrowed
variant, this
conversion allocates on the heap and copies the
underlying str
. Otherwise, it will try to reuse the owned
String
’s allocation.
Examples
use std::borrow::Cow;
let unboxed = Cow::Borrowed("hello");
let boxed: Box<str> = Box::from(unboxed);
println!("{boxed}");
Runlet unboxed = Cow::Owned("hello".to_string());
let boxed: Box<str> = Box::from(unboxed);
println!("{boxed}");
Run1.22.0 · sourceimpl<'a> From<Cow<'a, str>> for Box<dyn Error>
impl<'a> From<Cow<'a, str>> for Box<dyn Error>
1.22.0 · sourceimpl<'a, 'b> From<Cow<'b, str>> for Box<dyn Error + Send + Sync + 'a>
impl<'a, 'b> From<Cow<'b, str>> for Box<dyn Error + Send + Sync + 'a>
sourcefn from(err: Cow<'b, str>) -> Box<dyn Error + Send + Sync + 'a>ⓘNotable traits for Box<I, A>impl<I: Iterator + ?Sized, A: Allocator> Iterator for Box<I, A> type Item = I::Item;impl<F: ?Sized + Future + Unpin, A: Allocator> Future for Box<F, A>where
A: 'static, type Output = F::Output;
fn from(err: Cow<'b, str>) -> Box<dyn Error + Send + Sync + 'a>ⓘNotable traits for Box<I, A>impl<I: Iterator + ?Sized, A: Allocator> Iterator for Box<I, A> type Item = I::Item;impl<F: ?Sized + Future + Unpin, A: Allocator> Future for Box<F, A>where
A: 'static, type Output = F::Output;
A: 'static, type Output = F::Output;
Converts a Cow
into a box of dyn Error
+ Send
+ Sync
.
Examples
use std::error::Error;
use std::mem;
use std::borrow::Cow;
let a_cow_str_error = Cow::from("a str error");
let a_boxed_error = Box::<dyn Error + Send + Sync>::from(a_cow_str_error);
assert!(
mem::size_of::<Box<dyn Error + Send + Sync>>() == mem::size_of_val(&a_boxed_error))
Runsourceimpl<'a, E: Error + 'a> From<E> for Box<dyn Error + 'a>
impl<'a, E: Error + 'a> From<E> for Box<dyn Error + 'a>
sourcefn from(err: E) -> Box<dyn Error + 'a>ⓘNotable traits for Box<I, A>impl<I: Iterator + ?Sized, A: Allocator> Iterator for Box<I, A> type Item = I::Item;impl<F: ?Sized + Future + Unpin, A: Allocator> Future for Box<F, A>where
A: 'static, type Output = F::Output;
fn from(err: E) -> Box<dyn Error + 'a>ⓘNotable traits for Box<I, A>impl<I: Iterator + ?Sized, A: Allocator> Iterator for Box<I, A> type Item = I::Item;impl<F: ?Sized + Future + Unpin, A: Allocator> Future for Box<F, A>where
A: 'static, type Output = F::Output;
A: 'static, type Output = F::Output;
Converts a type of Error
into a box of dyn Error
.
Examples
use std::error::Error;
use std::fmt;
use std::mem;
#[derive(Debug)]
struct AnError;
impl fmt::Display for AnError {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(f, "An error")
}
}
impl Error for AnError {}
let an_error = AnError;
assert!(0 == mem::size_of_val(&an_error));
let a_boxed_error = Box::<dyn Error>::from(an_error);
assert!(mem::size_of::<Box<dyn Error>>() == mem::size_of_val(&a_boxed_error))
Runsourceimpl<'a, E: Error + Send + Sync + 'a> From<E> for Box<dyn Error + Send + Sync + 'a>
impl<'a, E: Error + Send + Sync + 'a> From<E> for Box<dyn Error + Send + Sync + 'a>
sourcefn from(err: E) -> Box<dyn Error + Send + Sync + 'a>ⓘNotable traits for Box<I, A>impl<I: Iterator + ?Sized, A: Allocator> Iterator for Box<I, A> type Item = I::Item;impl<F: ?Sized + Future + Unpin, A: Allocator> Future for Box<F, A>where
A: 'static, type Output = F::Output;
fn from(err: E) -> Box<dyn Error + Send + Sync + 'a>ⓘNotable traits for Box<I, A>impl<I: Iterator + ?Sized, A: Allocator> Iterator for Box<I, A> type Item = I::Item;impl<F: ?Sized + Future + Unpin, A: Allocator> Future for Box<F, A>where
A: 'static, type Output = F::Output;
A: 'static, type Output = F::Output;
Converts a type of Error
+ Send
+ Sync
into a box of
dyn Error
+ Send
+ Sync
.
Examples
use std::error::Error;
use std::fmt;
use std::mem;
#[derive(Debug)]
struct AnError;
impl fmt::Display for AnError {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(f, "An error")
}
}
impl Error for AnError {}
unsafe impl Send for AnError {}
unsafe impl Sync for AnError {}
let an_error = AnError;
assert!(0 == mem::size_of_val(&an_error));
let a_boxed_error = Box::<dyn Error + Send + Sync>::from(an_error);
assert!(
mem::size_of::<Box<dyn Error + Send + Sync>>() == mem::size_of_val(&a_boxed_error))
Runsourceimpl From<String> for Box<dyn Error + Send + Sync>
impl From<String> for Box<dyn Error + Send + Sync>
sourcefn from(err: String) -> Box<dyn Error + Send + Sync>ⓘNotable traits for Box<I, A>impl<I: Iterator + ?Sized, A: Allocator> Iterator for Box<I, A> type Item = I::Item;impl<F: ?Sized + Future + Unpin, A: Allocator> Future for Box<F, A>where
A: 'static, type Output = F::Output;
fn from(err: String) -> Box<dyn Error + Send + Sync>ⓘNotable traits for Box<I, A>impl<I: Iterator + ?Sized, A: Allocator> Iterator for Box<I, A> type Item = I::Item;impl<F: ?Sized + Future + Unpin, A: Allocator> Future for Box<F, A>where
A: 'static, type Output = F::Output;
A: 'static, type Output = F::Output;
Converts a String
into a box of dyn Error
+ Send
+ Sync
.
Examples
use std::error::Error;
use std::mem;
let a_string_error = "a string error".to_string();
let a_boxed_error = Box::<dyn Error + Send + Sync>::from(a_string_error);
assert!(
mem::size_of::<Box<dyn Error + Send + Sync>>() == mem::size_of_val(&a_boxed_error))
Run1.6.0 · sourceimpl From<String> for Box<dyn Error>
impl From<String> for Box<dyn Error>
1.20.0 · sourceimpl From<String> for Box<str>
impl From<String> for Box<str>
1.32.0 · sourceimpl<I> FromIterator<I> for Box<[I]>
impl<I> FromIterator<I> for Box<[I]>
sourcefn from_iter<T: IntoIterator<Item = I>>(iter: T) -> Self
fn from_iter<T: IntoIterator<Item = I>>(iter: T) -> Self
sourceimpl<G: ?Sized + Generator<R> + Unpin, R, A: Allocator> Generator<R> for Box<G, A>where
A: 'static,
impl<G: ?Sized + Generator<R> + Unpin, R, A: Allocator> Generator<R> for Box<G, A>where
A: 'static,
type Yield = <G as Generator<R>>::Yield
type Yield = <G as Generator<R>>::Yield
generator_trait
#43122)sourceimpl<G: ?Sized + Generator<R>, R, A: Allocator> Generator<R> for Pin<Box<G, A>>where
A: 'static,
impl<G: ?Sized + Generator<R>, R, A: Allocator> Generator<R> for Pin<Box<G, A>>where
A: 'static,
type Yield = <G as Generator<R>>::Yield
type Yield = <G as Generator<R>>::Yield
generator_trait
#43122)1.22.0 · sourceimpl<T: ?Sized + Hasher, A: Allocator> Hasher for Box<T, A>
impl<T: ?Sized + Hasher, A: Allocator> Hasher for Box<T, A>
sourcefn write_u128(&mut self, i: u128)
fn write_u128(&mut self, i: u128)
u128
into this hasher.sourcefn write_usize(&mut self, i: usize)
fn write_usize(&mut self, i: usize)
usize
into this hasher.sourcefn write_i128(&mut self, i: i128)
fn write_i128(&mut self, i: i128)
i128
into this hasher.sourcefn write_isize(&mut self, i: isize)
fn write_isize(&mut self, i: isize)
isize
into this hasher.sourcefn write_length_prefix(&mut self, len: usize)
fn write_length_prefix(&mut self, len: usize)
hasher_prefixfree_extras
#96762)sourceimpl<I: Iterator + ?Sized, A: Allocator> Iterator for Box<I, A>
impl<I: Iterator + ?Sized, A: Allocator> Iterator for Box<I, A>
sourcefn next(&mut self) -> Option<I::Item>
fn next(&mut self) -> Option<I::Item>
sourcefn size_hint(&self) -> (usize, Option<usize>)
fn size_hint(&self) -> (usize, Option<usize>)
sourcefn nth(&mut self, n: usize) -> Option<I::Item>
fn nth(&mut self, n: usize) -> Option<I::Item>
n
th element of the iterator. Read moresourcefn next_chunk<const N: usize>(
&mut self
) -> Result<[Self::Item; N], IntoIter<Self::Item, N>>
fn next_chunk<const N: usize>(
&mut self
) -> Result<[Self::Item; N], IntoIter<Self::Item, N>>
iter_next_chunk
#98326)N
values. Read moresourcefn count(self) -> usize
fn count(self) -> usize
sourcefn advance_by(&mut self, n: usize) -> Result<(), usize>
fn advance_by(&mut self, n: usize) -> Result<(), usize>
iter_advance_by
#77404)n
elements. Read more1.28.0 · sourcefn step_by(self, step: usize) -> StepBy<Self>
fn step_by(self, step: usize) -> StepBy<Self>
sourcefn chain<U>(self, other: U) -> Chain<Self, <U as IntoIterator>::IntoIter>where
U: IntoIterator<Item = Self::Item>,
fn chain<U>(self, other: U) -> Chain<Self, <U as IntoIterator>::IntoIter>where
U: IntoIterator<Item = Self::Item>,
sourcefn zip<U>(self, other: U) -> Zip<Self, <U as IntoIterator>::IntoIter>where
U: IntoIterator,
fn zip<U>(self, other: U) -> Zip<Self, <U as IntoIterator>::IntoIter>where
U: IntoIterator,
sourcefn intersperse_with<G>(self, separator: G) -> IntersperseWith<Self, G>where
G: FnMut() -> Self::Item,
fn intersperse_with<G>(self, separator: G) -> IntersperseWith<Self, G>where
G: FnMut() -> Self::Item,
iter_intersperse
#79524)separator
between adjacent items of the original iterator. Read moresourcefn map<B, F>(self, f: F) -> Map<Self, F>where
F: FnMut(Self::Item) -> B,
fn map<B, F>(self, f: F) -> Map<Self, F>where
F: FnMut(Self::Item) -> B,
1.21.0 · sourcefn for_each<F>(self, f: F)where
F: FnMut(Self::Item),
fn for_each<F>(self, f: F)where
F: FnMut(Self::Item),
sourcefn filter<P>(self, predicate: P) -> Filter<Self, P>where
P: FnMut(&Self::Item) -> bool,
fn filter<P>(self, predicate: P) -> Filter<Self, P>where
P: FnMut(&Self::Item) -> bool,
sourcefn filter_map<B, F>(self, f: F) -> FilterMap<Self, F>where
F: FnMut(Self::Item) -> Option<B>,
fn filter_map<B, F>(self, f: F) -> FilterMap<Self, F>where
F: FnMut(Self::Item) -> Option<B>,
sourcefn enumerate(self) -> Enumerate<Self>
fn enumerate(self) -> Enumerate<Self>
sourcefn skip_while<P>(self, predicate: P) -> SkipWhile<Self, P>where
P: FnMut(&Self::Item) -> bool,
fn skip_while<P>(self, predicate: P) -> SkipWhile<Self, P>where
P: FnMut(&Self::Item) -> bool,
sourcefn take_while<P>(self, predicate: P) -> TakeWhile<Self, P>where
P: FnMut(&Self::Item) -> bool,
fn take_while<P>(self, predicate: P) -> TakeWhile<Self, P>where
P: FnMut(&Self::Item) -> bool,
1.57.0 · sourcefn map_while<B, P>(self, predicate: P) -> MapWhile<Self, P>where
P: FnMut(Self::Item) -> Option<B>,
fn map_while<B, P>(self, predicate: P) -> MapWhile<Self, P>where
P: FnMut(Self::Item) -> Option<B>,
sourcefn skip(self, n: usize) -> Skip<Self>
fn skip(self, n: usize) -> Skip<Self>
n
elements. Read moresourcefn take(self, n: usize) -> Take<Self>
fn take(self, n: usize) -> Take<Self>
n
elements, or fewer
if the underlying iterator ends sooner. Read moresourcefn scan<St, B, F>(self, initial_state: St, f: F) -> Scan<Self, St, F>where
F: FnMut(&mut St, Self::Item) -> Option<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>,
sourcefn flat_map<U, F>(self, f: F) -> FlatMap<Self, U, F>where
U: IntoIterator,
F: FnMut(Self::Item) -> U,
fn flat_map<U, F>(self, f: F) -> FlatMap<Self, U, F>where
U: IntoIterator,
F: FnMut(Self::Item) -> U,
sourcefn inspect<F>(self, f: F) -> Inspect<Self, F>where
F: FnMut(&Self::Item),
fn inspect<F>(self, f: F) -> Inspect<Self, F>where
F: FnMut(&Self::Item),
sourcefn collect<B>(self) -> Bwhere
B: FromIterator<Self::Item>,
fn collect<B>(self) -> Bwhere
B: FromIterator<Self::Item>,
sourcefn collect_into<E>(self, collection: &mut E) -> &mut Ewhere
E: Extend<Self::Item>,
fn collect_into<E>(self, collection: &mut E) -> &mut Ewhere
E: Extend<Self::Item>,
iter_collect_into
#94780)sourcefn partition<B, F>(self, f: F) -> (B, B)where
B: Default + Extend<Self::Item>,
F: FnMut(&Self::Item) -> bool,
fn partition<B, F>(self, f: F) -> (B, B)where
B: Default + Extend<Self::Item>,
F: FnMut(&Self::Item) -> bool,
sourcefn is_partitioned<P>(self, predicate: P) -> boolwhere
P: FnMut(Self::Item) -> bool,
fn is_partitioned<P>(self, predicate: P) -> boolwhere
P: FnMut(Self::Item) -> bool,
iter_is_partitioned
#62544)true
precede all those that return false
. Read more1.27.0 · sourcefn try_fold<B, F, R>(&mut self, init: B, f: F) -> Rwhere
F: FnMut(B, Self::Item) -> R,
R: Try<Output = B>,
fn try_fold<B, F, R>(&mut self, init: B, f: F) -> Rwhere
F: FnMut(B, Self::Item) -> R,
R: Try<Output = B>,
1.27.0 · sourcefn try_for_each<F, R>(&mut self, f: F) -> Rwhere
F: FnMut(Self::Item) -> R,
R: Try<Output = ()>,
fn try_for_each<F, R>(&mut self, f: F) -> Rwhere
F: FnMut(Self::Item) -> R,
R: Try<Output = ()>,
sourcefn fold<B, F>(self, init: B, f: F) -> Bwhere
F: FnMut(B, Self::Item) -> B,
fn fold<B, F>(self, init: B, f: F) -> Bwhere
F: FnMut(B, Self::Item) -> B,
1.51.0 · sourcefn reduce<F>(self, f: F) -> Option<Self::Item>where
F: FnMut(Self::Item, Self::Item) -> Self::Item,
fn reduce<F>(self, f: F) -> Option<Self::Item>where
F: FnMut(Self::Item, Self::Item) -> Self::Item,
sourcefn try_reduce<F, R>(
&mut self,
f: F
) -> <<R as Try>::Residual as Residual<Option<<R as Try>::Output>>>::TryTypewhere
F: FnMut(Self::Item, Self::Item) -> R,
R: Try<Output = Self::Item>,
<R as Try>::Residual: Residual<Option<Self::Item>>,
fn try_reduce<F, R>(
&mut self,
f: F
) -> <<R as Try>::Residual as Residual<Option<<R as Try>::Output>>>::TryTypewhere
F: FnMut(Self::Item, Self::Item) -> R,
R: Try<Output = Self::Item>,
<R as Try>::Residual: Residual<Option<Self::Item>>,
iterator_try_reduce
#87053)sourcefn all<F>(&mut self, f: F) -> boolwhere
F: FnMut(Self::Item) -> bool,
fn all<F>(&mut self, f: F) -> boolwhere
F: FnMut(Self::Item) -> bool,
sourcefn any<F>(&mut self, f: F) -> boolwhere
F: FnMut(Self::Item) -> bool,
fn any<F>(&mut self, f: F) -> boolwhere
F: FnMut(Self::Item) -> bool,
sourcefn find<P>(&mut self, predicate: P) -> Option<Self::Item>where
P: FnMut(&Self::Item) -> bool,
fn find<P>(&mut self, predicate: P) -> Option<Self::Item>where
P: FnMut(&Self::Item) -> bool,
1.30.0 · sourcefn find_map<B, F>(&mut self, f: F) -> Option<B>where
F: FnMut(Self::Item) -> Option<B>,
fn find_map<B, F>(&mut self, f: F) -> Option<B>where
F: FnMut(Self::Item) -> Option<B>,
sourcefn try_find<F, R>(
&mut self,
f: F
) -> <<R as Try>::Residual as Residual<Option<Self::Item>>>::TryTypewhere
F: FnMut(&Self::Item) -> R,
R: Try<Output = bool>,
<R as Try>::Residual: Residual<Option<Self::Item>>,
fn try_find<F, R>(
&mut self,
f: F
) -> <<R as Try>::Residual as Residual<Option<Self::Item>>>::TryTypewhere
F: FnMut(&Self::Item) -> R,
R: Try<Output = bool>,
<R as Try>::Residual: Residual<Option<Self::Item>>,
try_find
#63178)sourcefn position<P>(&mut self, predicate: P) -> Option<usize>where
P: FnMut(Self::Item) -> bool,
fn position<P>(&mut self, predicate: P) -> Option<usize>where
P: FnMut(Self::Item) -> bool,
1.6.0 · sourcefn max_by_key<B, F>(self, f: F) -> Option<Self::Item>where
B: Ord,
F: FnMut(&Self::Item) -> B,
fn max_by_key<B, F>(self, f: F) -> Option<Self::Item>where
B: Ord,
F: FnMut(&Self::Item) -> B,
1.15.0 · sourcefn max_by<F>(self, compare: F) -> Option<Self::Item>where
F: FnMut(&Self::Item, &Self::Item) -> Ordering,
fn max_by<F>(self, compare: F) -> Option<Self::Item>where
F: FnMut(&Self::Item, &Self::Item) -> Ordering,
1.6.0 · sourcefn min_by_key<B, F>(self, f: F) -> Option<Self::Item>where
B: Ord,
F: FnMut(&Self::Item) -> B,
fn min_by_key<B, F>(self, f: F) -> Option<Self::Item>where
B: Ord,
F: FnMut(&Self::Item) -> B,
1.15.0 · sourcefn min_by<F>(self, compare: F) -> Option<Self::Item>where
F: FnMut(&Self::Item, &Self::Item) -> Ordering,
fn min_by<F>(self, compare: F) -> Option<Self::Item>where
F: FnMut(&Self::Item, &Self::Item) -> Ordering,
sourcefn unzip<A, B, FromA, FromB>(self) -> (FromA, FromB)where
FromA: Default + Extend<A>,
FromB: Default + Extend<B>,
Self: Iterator<Item = (A, B)>,
fn unzip<A, B, FromA, FromB>(self) -> (FromA, FromB)where
FromA: Default + Extend<A>,
FromB: Default + Extend<B>,
Self: Iterator<Item = (A, B)>,
1.36.0 · sourcefn copied<'a, T>(self) -> Copied<Self>where
T: 'a + Copy,
Self: Iterator<Item = &'a T>,
fn copied<'a, T>(self) -> Copied<Self>where
T: 'a + Copy,
Self: Iterator<Item = &'a T>,
sourcefn array_chunks<const N: usize>(self) -> ArrayChunks<Self, N>
fn array_chunks<const N: usize>(self) -> ArrayChunks<Self, N>
iter_array_chunks
#100450)N
elements of the iterator at a time. Read more1.11.0 · sourcefn sum<S>(self) -> Swhere
S: Sum<Self::Item>,
fn sum<S>(self) -> Swhere
S: Sum<Self::Item>,
1.11.0 · sourcefn product<P>(self) -> Pwhere
P: Product<Self::Item>,
fn product<P>(self) -> Pwhere
P: Product<Self::Item>,
sourcefn cmp_by<I, F>(self, other: I, cmp: F) -> Orderingwhere
I: IntoIterator,
F: FnMut(Self::Item, <I as IntoIterator>::Item) -> Ordering,
fn cmp_by<I, F>(self, other: I, cmp: F) -> Orderingwhere
I: IntoIterator,
F: FnMut(Self::Item, <I as IntoIterator>::Item) -> Ordering,
iter_order_by
#64295)Iterator
with those
of another with respect to the specified comparison function. Read more1.5.0 · sourcefn partial_cmp<I>(self, other: I) -> Option<Ordering>where
I: IntoIterator,
Self::Item: PartialOrd<<I as IntoIterator>::Item>,
fn partial_cmp<I>(self, other: I) -> Option<Ordering>where
I: IntoIterator,
Self::Item: PartialOrd<<I as IntoIterator>::Item>,
sourcefn partial_cmp_by<I, F>(self, other: I, partial_cmp: F) -> Option<Ordering>where
I: IntoIterator,
F: FnMut(Self::Item, <I as IntoIterator>::Item) -> Option<Ordering>,
fn partial_cmp_by<I, F>(self, other: I, partial_cmp: F) -> Option<Ordering>where
I: IntoIterator,
F: FnMut(Self::Item, <I as IntoIterator>::Item) -> Option<Ordering>,
iter_order_by
#64295)Iterator
with those
of another with respect to the specified comparison function. Read more1.5.0 · sourcefn eq<I>(self, other: I) -> boolwhere
I: IntoIterator,
Self::Item: PartialEq<<I as IntoIterator>::Item>,
fn eq<I>(self, other: I) -> boolwhere
I: IntoIterator,
Self::Item: PartialEq<<I as IntoIterator>::Item>,
sourcefn eq_by<I, F>(self, other: I, eq: F) -> boolwhere
I: IntoIterator,
F: FnMut(Self::Item, <I as IntoIterator>::Item) -> bool,
fn eq_by<I, F>(self, other: I, eq: F) -> boolwhere
I: IntoIterator,
F: FnMut(Self::Item, <I as IntoIterator>::Item) -> bool,
iter_order_by
#64295)1.5.0 · sourcefn ne<I>(self, other: I) -> boolwhere
I: IntoIterator,
Self::Item: PartialEq<<I as IntoIterator>::Item>,
fn ne<I>(self, other: I) -> boolwhere
I: IntoIterator,
Self::Item: PartialEq<<I as IntoIterator>::Item>,
1.5.0 · sourcefn lt<I>(self, other: I) -> boolwhere
I: IntoIterator,
Self::Item: PartialOrd<<I as IntoIterator>::Item>,
fn lt<I>(self, other: I) -> boolwhere
I: IntoIterator,
Self::Item: PartialOrd<<I as IntoIterator>::Item>,
Iterator
are lexicographically
less than those of another. Read more1.5.0 · sourcefn le<I>(self, other: I) -> boolwhere
I: IntoIterator,
Self::Item: PartialOrd<<I as IntoIterator>::Item>,
fn le<I>(self, other: I) -> boolwhere
I: IntoIterator,
Self::Item: PartialOrd<<I as IntoIterator>::Item>,
Iterator
are lexicographically
less or equal to those of another. Read more1.5.0 · sourcefn gt<I>(self, other: I) -> boolwhere
I: IntoIterator,
Self::Item: PartialOrd<<I as IntoIterator>::Item>,
fn gt<I>(self, other: I) -> boolwhere
I: IntoIterator,
Self::Item: PartialOrd<<I as IntoIterator>::Item>,
Iterator
are lexicographically
greater than those of another. Read more1.5.0 · sourcefn ge<I>(self, other: I) -> boolwhere
I: IntoIterator,
Self::Item: PartialOrd<<I as IntoIterator>::Item>,
fn ge<I>(self, other: I) -> boolwhere
I: IntoIterator,
Self::Item: PartialOrd<<I as IntoIterator>::Item>,
Iterator
are lexicographically
greater than or equal to those of another. Read moresourcefn is_sorted_by<F>(self, compare: F) -> boolwhere
F: FnMut(&Self::Item, &Self::Item) -> Option<Ordering>,
fn is_sorted_by<F>(self, compare: F) -> boolwhere
F: FnMut(&Self::Item, &Self::Item) -> Option<Ordering>,
is_sorted
#53485)sourcefn is_sorted_by_key<F, K>(self, f: F) -> boolwhere
F: FnMut(Self::Item) -> K,
K: PartialOrd<K>,
fn is_sorted_by_key<F, K>(self, f: F) -> boolwhere
F: FnMut(Self::Item) -> K,
K: PartialOrd<K>,
is_sorted
#53485)sourceimpl<T: ?Sized + Ord, A: Allocator> Ord for Box<T, A>
impl<T: ?Sized + Ord, A: Allocator> Ord for Box<T, A>
1.21.0 · sourcefn max(self, other: Self) -> Self
fn max(self, other: Self) -> Self
1.21.0 · sourcefn min(self, other: Self) -> Self
fn min(self, other: Self) -> Self
1.50.0 · sourcefn clamp(self, min: Self, max: Self) -> Selfwhere
Self: PartialOrd<Self>,
fn clamp(self, min: Self, max: Self) -> Selfwhere
Self: PartialOrd<Self>,
sourceimpl<T: ?Sized + PartialEq, A: Allocator> PartialEq<Box<T, A>> for Box<T, A>
impl<T: ?Sized + PartialEq, A: Allocator> PartialEq<Box<T, A>> for Box<T, A>
sourceimpl<T: ?Sized + PartialOrd, A: Allocator> PartialOrd<Box<T, A>> for Box<T, A>
impl<T: ?Sized + PartialOrd, A: Allocator> PartialOrd<Box<T, A>> for Box<T, A>
sourcefn partial_cmp(&self, other: &Self) -> Option<Ordering>
fn partial_cmp(&self, other: &Self) -> Option<Ordering>
sourcefn le(&self, other: &Self) -> bool
fn le(&self, other: &Self) -> bool
self
and other
) and is used by the <=
operator. Read more1.43.0 · sourceimpl<T, const N: usize> TryFrom<Box<[T], Global>> for Box<[T; N]>
impl<T, const N: usize> TryFrom<Box<[T], Global>> for Box<[T; N]>
impl<T: ?Sized + Unsize<U>, U: ?Sized, A: Allocator> CoerceUnsized<Box<U, A>> for Box<T, A>
impl<T: ?Sized + Unsize<U>, U: ?Sized> DispatchFromDyn<Box<U, Global>> for Box<T, Global>
impl<T: ?Sized + Eq, A: Allocator> Eq for Box<T, A>
impl<I: FusedIterator + ?Sized, A: Allocator> FusedIterator for Box<I, A>
impl<T: ?Sized, A: Allocator> Unpin for Box<T, A>where
A: 'static,
Auto Trait Implementations
impl<T: ?Sized, A> RefUnwindSafe for Box<T, A>where
A: RefUnwindSafe,
T: RefUnwindSafe,
impl<T: ?Sized, A> Send for Box<T, A>where
A: Send,
T: Send,
impl<T: ?Sized, A> Sync for Box<T, A>where
A: Sync,
T: Sync,
impl<T: ?Sized, A> UnwindSafe for Box<T, A>where
A: UnwindSafe,
T: UnwindSafe,
Blanket Implementations
sourceimpl<T> BorrowMut<T> for Twhere
T: ?Sized,
impl<T> BorrowMut<T> for Twhere
T: ?Sized,
const: unstable · sourcefn borrow_mut(&mut self) -> &mut T
fn borrow_mut(&mut self) -> &mut T
sourceimpl<F> IntoFuture for Fwhere
F: Future,
impl<F> IntoFuture for Fwhere
F: Future,
type IntoFuture = F
type IntoFuture = F
sourcefn into_future(self) -> <F as IntoFuture>::IntoFuture
fn into_future(self) -> <F as IntoFuture>::IntoFuture
sourceimpl<I> IntoIterator for Iwhere
I: Iterator,
impl<I> IntoIterator for Iwhere
I: Iterator,
sourceimpl<'a, F> Pattern<'a> for Fwhere
F: FnMut(char) -> bool,
impl<'a, F> Pattern<'a> for Fwhere
F: FnMut(char) -> bool,
type Searcher = CharPredicateSearcher<'a, F>
type Searcher = CharPredicateSearcher<'a, F>
pattern
#27721)sourcefn into_searcher(self, haystack: &'a str) -> CharPredicateSearcher<'a, F>
fn into_searcher(self, haystack: &'a str) -> CharPredicateSearcher<'a, F>
pattern
#27721)sourcefn is_contained_in(self, haystack: &'a str) -> bool
fn is_contained_in(self, haystack: &'a str) -> bool
pattern
#27721)sourcefn is_prefix_of(self, haystack: &'a str) -> bool
fn is_prefix_of(self, haystack: &'a str) -> bool
pattern
#27721)sourcefn strip_prefix_of(self, haystack: &'a str) -> Option<&'a str>
fn strip_prefix_of(self, haystack: &'a str) -> Option<&'a str>
pattern
#27721)sourcefn is_suffix_of(self, haystack: &'a str) -> boolwhere
CharPredicateSearcher<'a, F>: ReverseSearcher<'a>,
fn is_suffix_of(self, haystack: &'a str) -> boolwhere
CharPredicateSearcher<'a, F>: ReverseSearcher<'a>,
pattern
#27721)sourcefn strip_suffix_of(self, haystack: &'a str) -> Option<&'a str>where
CharPredicateSearcher<'a, F>: ReverseSearcher<'a>,
fn strip_suffix_of(self, haystack: &'a str) -> Option<&'a str>where
CharPredicateSearcher<'a, F>: ReverseSearcher<'a>,
pattern
#27721)