Struct Box &nbsp; Copy item path

impl<A> Box<dyn Any, A>
where A: Allocator,

1.0.0 · Source

pub fn downcast<T>(self) -> Result<Box<T, A>, Box<dyn Any, A>>
where T: Any,

Attempts 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));

pub unsafe fn downcast_unchecked<T>(self) -> Box<T, A>
where T: Any,

🔬This is a nightly-only experimental API. (downcast_unchecked)

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);
}

§Safety

The contained value must be of type T. Calling this method with the incorrect type is undefined behavior.

impl<A> Box<dyn Any + Send, A>
where A: Allocator,

1.0.0 · Source

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

Attempts 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));

pub unsafe fn downcast_unchecked<T>(self) -> Box<T, A>
where T: Any,

🔬This is a nightly-only experimental API. (downcast_unchecked)

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);
}

§Safety

The contained value must be of type T. Calling this method with the incorrect type is undefined behavior.

impl<A> Box<dyn Any + Sync + Send, A>
where A: Allocator,

1.51.0 · Source

pub fn downcast<T>(self) -> Result<Box<T, A>, Box<dyn Any + Sync + Send, A>>
where T: Any,

Attempts 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));

pub unsafe fn downcast_unchecked<T>(self) -> Box<T, A>
where T: Any,

🔬This is a nightly-only experimental API. (downcast_unchecked)

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);
}

§Safety

The contained value must be of type T. Calling this method with the incorrect type is undefined behavior.

impl<T> Box<T>

1.0.0 · Source

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

Available on non-no_global_oom_handling only.

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);

1.82.0 · Source

pub fn new_uninit() -> Box<MaybeUninit<T>>

Available on non-no_global_oom_handling only.

Constructs a new box with uninitialized contents.

§Examples

let mut five = Box::<u32>::new_uninit();
// Deferred initialization:
five.write(5);
let five = unsafe { five.assume_init() };

assert_eq!(*five, 5)

1.92.0 · Source

pub fn new_zeroed() -> Box<MaybeUninit<T>>

Available on non-no_global_oom_handling only.

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

let zero = Box::<u32>::new_zeroed();
let zero = unsafe { zero.assume_init() };

assert_eq!(*zero, 0)

1.33.0 · Source

pub fn pin(x: T) -> Pin<Box<T>>

Available on non-no_global_oom_handling only.

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.

pub fn try_new(x: T) -> Result<Box<T>, AllocError>

🔬This is a nightly-only experimental API. (allocator_api)

Allocates memory on the heap then places x into it, returning an error if the allocation fails

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

§Examples

#![feature(allocator_api)]

let five = Box::try_new(5)?;

pub fn try_new_uninit() -> Result<Box<MaybeUninit<T>>, AllocError>

🔬This is a nightly-only experimental API. (allocator_api)

Constructs a new box with uninitialized contents on the heap, returning an error if the allocation fails

§Examples

#![feature(allocator_api)]

let mut five = Box::<u32>::try_new_uninit()?;
// Deferred initialization:
five.write(5);
let five = unsafe { five.assume_init() };

assert_eq!(*five, 5);

pub fn try_new_zeroed() -> Result<Box<MaybeUninit<T>>, AllocError>

🔬This is a nightly-only experimental API. (allocator_api)

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)]

let zero = Box::<u32>::try_new_zeroed()?;
let zero = unsafe { zero.assume_init() };

assert_eq!(*zero, 0);

pub fn map(this: Box<T>, f: impl FnOnce(T) -> U) -> Box

🔬This is a nightly-only experimental API. (smart_pointer_try_map)

Available on non-no_global_oom_handling only.

Maps the value in a box, reusing the allocation if possible.

f is called on the value in the box, and the result is returned, also boxed.

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

§Examples

#![feature(smart_pointer_try_map)]

let b = Box::new(7);
let new = Box::map(b, |i| i + 7);
assert_eq!(*new, 14);

pub fn try_map<R>( this: Box<T>, f: impl FnOnce(T) -> R, ) -> <<R as Try>::Residual as Residual<Box<<R as Try>::Output>>>::TryType
where R: Try, <R as Try>::Residual: Residual<Box<<R as Try>::Output>>,

🔬This is a nightly-only experimental API. (smart_pointer_try_map)

Available on non-no_global_oom_handling only.

Attempts to map the value in a box, reusing the allocation if possible.

f is called on the value in the box, and if the operation succeeds, the result is returned, also boxed.

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

§Examples

#![feature(smart_pointer_try_map)]

let b = Box::new(7);
let new = Box::try_map(b, u32::try_from).unwrap();
assert_eq!(*new, 7);

impl<T, A> Box<T, A>
where A: Allocator,

pub fn new_in(x: T, alloc: A) -> Box<T, A>
where A: Allocator,

🔬This is a nightly-only experimental API. (allocator_api)

Available on non-no_global_oom_handling only.

Allocates memory in the given allocator then places x into it.

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

§Examples

#![feature(allocator_api)]

use std::alloc::System;

let five = Box::new_in(5, System);

pub fn try_new_in(x: T, alloc: A) -> Result<Box<T, A>, AllocError>
where A: Allocator,

🔬This is a nightly-only experimental API. (allocator_api)

Allocates memory in the given allocator then places x into it, returning an error if the allocation fails

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

§Examples

#![feature(allocator_api)]

use std::alloc::System;

let five = Box::try_new_in(5, System)?;

pub fn new_uninit_in(alloc: A) -> Box<MaybeUninit<T>, A>
where A: Allocator,

🔬This is a nightly-only experimental API. (allocator_api)

Available on non-no_global_oom_handling only.

Constructs a new box with uninitialized contents in the provided allocator.

§Examples

#![feature(allocator_api)]

use std::alloc::System;

let mut five = Box::<u32, _>::new_uninit_in(System);
// Deferred initialization:
five.write(5);
let five = unsafe { five.assume_init() };

assert_eq!(*five, 5)

pub 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)

Constructs a new box with uninitialized contents in the provided allocator, returning an error if the allocation fails

§Examples

#![feature(allocator_api)]

use std::alloc::System;

let mut five = Box::<u32, _>::try_new_uninit_in(System)?;
// Deferred initialization:
five.write(5);
let five = unsafe { five.assume_init() };

assert_eq!(*five, 5);

pub fn new_zeroed_in(alloc: A) -> Box<MaybeUninit<T>, A>
where A: Allocator,

🔬This is a nightly-only experimental API. (allocator_api)

Available on non-no_global_oom_handling only.

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)]

use std::alloc::System;

let zero = Box::<u32, _>::new_zeroed_in(System);
let zero = unsafe { zero.assume_init() };

assert_eq!(*zero, 0)

pub 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)

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)]

use std::alloc::System;

let zero = Box::<u32, _>::try_new_zeroed_in(System)?;
let zero = unsafe { zero.assume_init() };

assert_eq!(*zero, 0);

pub fn pin_in(x: T, alloc: A) -> Pin<Box<T, A>>
where A: 'static + Allocator,

🔬This is a nightly-only experimental API. (allocator_api)

Available on non-no_global_oom_handling only.

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.

§Examples

#![feature(allocator_api)]
use std::alloc::System;

let x = Box::pin_in(1, System);

pub fn into_boxed_slice(boxed: Box<T, A>) -> Box<[T], A>

🔬This is a nightly-only experimental API. (box_into_boxed_slice)

Converts a Box<T> into a Box<[T]>

This conversion does not allocate on the heap and happens in place.

pub fn into_inner(boxed: Box<T, A>) -> T

🔬This is a nightly-only experimental API. (box_into_inner)

Consumes the Box, returning the wrapped value.

§Examples

#![feature(box_into_inner)]

let c = Box::new(5);

assert_eq!(Box::into_inner(c), 5);

pub fn take(boxed: Box<T, A>) -> (T, Box<MaybeUninit<T>, A>)

🔬This is a nightly-only experimental API. (box_take)

Consumes the Box without consuming its allocation, returning the wrapped value and a Box to the uninitialized memory where the wrapped value used to live.

This can be used together with write to reuse the allocation for multiple boxed values.

§Examples

#![feature(box_take)]

let c = Box::new(5);

// take the value out of the box
let (value, uninit) = Box::take(c);
assert_eq!(value, 5);

// reuse the box for a second value
let c = Box::write(uninit, 6);
assert_eq!(*c, 6);

impl<T> Box<T>
where T: CloneToUninit + ?Sized,

pub fn clone_from_ref(src: &T) -> Box<T>

🔬This is a nightly-only experimental API. (clone_from_ref)

Available on non-no_global_oom_handling only.

Allocates memory on the heap then clones src into it.

This doesn’t actually allocate if src is zero-sized.

§Examples

#![feature(clone_from_ref)]

let hello: Box<str> = Box::clone_from_ref("hello");

pub fn try_clone_from_ref(src: &T) -> Result<Box<T>, AllocError>

🔬This is a nightly-only experimental API. (clone_from_ref)

Allocates memory on the heap then clones src into it, returning an error if allocation fails.

This doesn’t actually allocate if src is zero-sized.

§Examples

#![feature(clone_from_ref)]
#![feature(allocator_api)]

let hello: Box<str> = Box::try_clone_from_ref("hello")?;

impl<T, A> Box<T, A>
where T: CloneToUninit + ?Sized, A: Allocator,

pub fn clone_from_ref_in(src: &T, alloc: A) -> Box<T, A>

🔬This is a nightly-only experimental API. (clone_from_ref)

Available on non-no_global_oom_handling only.

Allocates memory in the given allocator then clones src into it.

This doesn’t actually allocate if src is zero-sized.

§Examples

#![feature(clone_from_ref)]
#![feature(allocator_api)]

use std::alloc::System;

let hello: Box<str, System> = Box::clone_from_ref_in("hello", System);

pub fn try_clone_from_ref_in(src: &T, alloc: A) -> Result<Box<T, A>, AllocError>

🔬This is a nightly-only experimental API. (clone_from_ref)

Allocates memory in the given allocator then clones src into it, returning an error if allocation fails.

This doesn’t actually allocate if src is zero-sized.

§Examples

#![feature(clone_from_ref)]
#![feature(allocator_api)]

use std::alloc::System;

let hello: Box<str, System> = Box::try_clone_from_ref_in("hello", System)?;

impl<T> Box<[T]>

1.82.0 · Source

pub fn new_uninit_slice(len: usize) -> Box<[MaybeUninit<T>]>

Available on non-no_global_oom_handling only.

Constructs a new boxed slice with uninitialized contents.

§Examples

let mut values = Box::<[u32]>::new_uninit_slice(3);
// Deferred initialization:
values[0].write(1);
values[1].write(2);
values[2].write(3);
let values = unsafe { values.assume_init() };

assert_eq!(*values, [1, 2, 3])

1.92.0 · Source

pub fn new_zeroed_slice(len: usize) -> Box<[MaybeUninit<T>]>

Available on non-no_global_oom_handling only.

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

let values = Box::<[u32]>::new_zeroed_slice(3);
let values = unsafe { values.assume_init() };

assert_eq!(*values, [0, 0, 0])

pub fn try_new_uninit_slice( len: usize, ) -> Result<Box<[MaybeUninit<T>]>, AllocError>

🔬This is a nightly-only experimental API. (allocator_api)

Constructs a new boxed slice with uninitialized contents. Returns an error if the allocation fails.

§Examples

#![feature(allocator_api)]

let mut values = Box::<[u32]>::try_new_uninit_slice(3)?;
// Deferred initialization:
values[0].write(1);
values[1].write(2);
values[2].write(3);
let values = unsafe { values.assume_init() };

assert_eq!(*values, [1, 2, 3]);

pub fn try_new_zeroed_slice( len: usize, ) -> Result<Box<[MaybeUninit<T>]>, AllocError>

🔬This is a nightly-only experimental API. (allocator_api)

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)]

let values = Box::<[u32]>::try_new_zeroed_slice(3)?;
let values = unsafe { values.assume_init() };

assert_eq!(*values, [0, 0, 0]);

impl<T, A> Box<[T], A>
where A: Allocator,

pub fn new_uninit_slice_in(len: usize, alloc: A) -> Box<[MaybeUninit<T>], A>

🔬This is a nightly-only experimental API. (allocator_api)

Available on non-no_global_oom_handling only.

Constructs a new boxed slice with uninitialized contents in the provided allocator.

§Examples

#![feature(allocator_api)]

use std::alloc::System;

let mut values = Box::<[u32], _>::new_uninit_slice_in(3, System);
// Deferred initialization:
values[0].write(1);
values[1].write(2);
values[2].write(3);
let values = unsafe { values.assume_init() };

assert_eq!(*values, [1, 2, 3])

pub fn new_zeroed_slice_in(len: usize, alloc: A) -> Box<[MaybeUninit<T>], A>

🔬This is a nightly-only experimental API. (allocator_api)

Available on non-no_global_oom_handling only.

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)]

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])

pub fn try_new_uninit_slice_in( len: usize, alloc: A, ) -> Result<Box<[MaybeUninit<T>], A>, AllocError>

🔬This is a nightly-only experimental API. (allocator_api)

Constructs a new boxed slice with uninitialized contents in the provided allocator. Returns an error if the allocation fails.

§Examples

#![feature(allocator_api)]

use std::alloc::System;

let mut values = Box::<[u32], _>::try_new_uninit_slice_in(3, System)?;
// Deferred initialization:
values[0].write(1);
values[1].write(2);
values[2].write(3);
let values = unsafe { values.assume_init() };

assert_eq!(*values, [1, 2, 3]);

pub fn try_new_zeroed_slice_in( len: usize, alloc: A, ) -> Result<Box<[MaybeUninit<T>], A>, AllocError>

🔬This is a nightly-only experimental API. (allocator_api)

Constructs a new boxed slice with uninitialized contents in the provided allocator, 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)]

use std::alloc::System;

let values = Box::<[u32], _>::try_new_zeroed_slice_in(3, System)?;
let values = unsafe { values.assume_init() };

assert_eq!(*values, [0, 0, 0]);

pub fn into_array<const N: usize>(self) -> Option<Box<[T; N], A>>

🔬This is a nightly-only experimental API. (alloc_slice_into_array)

Converts the boxed slice into a boxed array.

This operation does not reallocate; the underlying array of the slice is simply reinterpreted as an array type.

If N is not exactly equal to the length of self, then this method returns None.

§Examples

#![feature(alloc_slice_into_array)]
let box_slice: Box<[i32]> = Box::new([1, 2, 3]);

let box_array: Box<[i32; 3]> = box_slice.into_array().unwrap();

impl<T, A> Box<MaybeUninit<T>, A>
where A: Allocator,

1.82.0 · Source

pub unsafe fn assume_init(self) -> Box<T, A>

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

let mut five = Box::<u32>::new_uninit();
// Deferred initialization:
five.write(5);
let five: Box<u32> = unsafe { five.assume_init() };

assert_eq!(*five, 5)

1.87.0 · Source

pub fn write(boxed: Box<MaybeUninit<T>, A>, value: T) -> Box<T, A>

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

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);
}

impl<T, A> Box<[MaybeUninit<T>], A>
where A: Allocator,

1.82.0 · Source

pub unsafe fn assume_init(self) -> Box<[T], A>

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

let mut values = Box::<[u32]>::new_uninit_slice(3);
// Deferred initialization:
values[0].write(1);
values[1].write(2);
values[2].write(3);
let values = unsafe { values.assume_init() };

assert_eq!(*values, [1, 2, 3])

impl<T> Box<T>
where T: ?Sized,

1.4.0 · Source

pub unsafe fn from_raw(raw: *mut T) -> Box<T>

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 raw pointer must point to a block of memory allocated by the global allocator.

The safety conditions are described in the memory layout section. Note that the considerations for unsafe code apply to all Box<T> values.

§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) };

Manually 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);
}

pub unsafe fn from_non_null(ptr: NonNull<T>) -> Box<T>

🔬This is a nightly-only experimental API. (box_vec_non_null)

Constructs a box from a NonNull pointer.

After calling this function, the NonNull 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 NonNull pointer.

The non-null pointer must point to a block of memory allocated by the global allocator.

The safety conditions are described in the memory layout section. Note that the considerations for unsafe code apply to all Box<T> values.

§Examples

Recreate a Box which was previously converted to a NonNull pointer using Box::into_non_null:

#![feature(box_vec_non_null)]

let x = Box::new(5);
let non_null = Box::into_non_null(x);
let x = unsafe { Box::from_non_null(non_null) };

Manually create a Box from scratch by using the global allocator:

#![feature(box_vec_non_null)]

use std::alloc::{alloc, Layout};
use std::ptr::NonNull;

unsafe {
    let non_null = NonNull::new(alloc(Layout::new::<i32>()).cast::<i32>())
        .expect("allocation failed");
    // In general .write is required to avoid attempting to destruct
    // the (uninitialized) previous contents of `non_null`.
    non_null.write(5);
    let x = Box::from_non_null(non_null);
}

1.4.0 · Source

pub fn into_raw(b: Box<T>) -> *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) };

Manual 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 ptr = Box::into_raw(x);
unsafe {
    ptr::drop_in_place(ptr);
    dealloc(ptr as *mut u8, Layout::new::<String>());
}

Note: This is equivalent to the following:

let x = Box::new(String::from("Hello"));
let ptr = Box::into_raw(x);
unsafe {
    drop(Box::from_raw(ptr));
}

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

🔬This is a nightly-only experimental API. (box_vec_non_null)

Consumes the Box, returning a wrapped NonNull pointer.

The pointer will be properly aligned.

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 NonNull pointer back into a Box with the Box::from_non_null 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_non_null(b) instead of b.into_non_null(). This is so that there is no conflict with a method on the inner type.

§Examples

Converting the NonNull pointer back into a Box with Box::from_non_null for automatic cleanup:

#![feature(box_vec_non_null)]

let x = Box::new(String::from("Hello"));
let non_null = Box::into_non_null(x);
let x = unsafe { Box::from_non_null(non_null) };

Manual cleanup by explicitly running the destructor and deallocating the memory:

#![feature(box_vec_non_null)]

use std::alloc::{dealloc, Layout};

let x = Box::new(String::from("Hello"));
let non_null = Box::into_non_null(x);
unsafe {
    non_null.drop_in_place();
    dealloc(non_null.as_ptr().cast::<u8>(), Layout::new::<String>());
}

Note: This is equivalent to the following:

#![feature(box_vec_non_null)]

let x = Box::new(String::from("Hello"));
let non_null = Box::into_non_null(x);
unsafe {
    drop(Box::from_non_null(non_null));
}

impl<T, A> Box<T, A>
where A: Allocator, T: ?Sized,

pub unsafe fn from_raw_in(raw: *mut T, alloc: A) -> Box<T, A>

🔬This is a nightly-only experimental API. (allocator_api)

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.

The raw pointer must point to a block of memory allocated by alloc.

The safety conditions are described in the memory layout section. Note that the considerations for unsafe code apply to all Box<T, A> values.

§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) };

Manually 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);
}

pub unsafe fn from_non_null_in(raw: NonNull<T>, alloc: A) -> Box<T, A>

🔬This is a nightly-only experimental API. (allocator_api)

Constructs a box from a NonNull pointer in the given allocator.

After calling this function, the NonNull 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 non-null pointer must point to a block of memory allocated by alloc.

The safety conditions are described in the memory layout section. Note that the considerations for unsafe code apply to all Box<T, A> values.

§Examples

Recreate a Box which was previously converted to a NonNull pointer using Box::into_non_null_with_allocator:

#![feature(allocator_api)]

use std::alloc::System;

let x = Box::new_in(5, System);
let (non_null, alloc) = Box::into_non_null_with_allocator(x);
let x = unsafe { Box::from_non_null_in(non_null, alloc) };

Manually create a Box from scratch by using the system allocator:

#![feature(allocator_api)]

use std::alloc::{Allocator, Layout, System};

unsafe {
    let non_null = System.allocate(Layout::new::<i32>())?.cast::<i32>();
    // In general .write is required to avoid attempting to destruct
    // the (uninitialized) previous contents of `non_null`.
    non_null.write(5);
    let x = Box::from_non_null_in(non_null, System);
}

pub fn into_raw_with_allocator(b: Box<T, A>) -> (*mut T, A)

🔬This is a nightly-only experimental API. (allocator_api)

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) };

Manual 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>());
}

pub fn into_non_null_with_allocator(b: Box<T, A>) -> (NonNull<T>, A)

🔬This is a nightly-only experimental API. (allocator_api)

Consumes the Box, returning a wrapped NonNull pointer and the allocator.

The pointer will be properly aligned.

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 NonNull pointer back into a Box with the Box::from_non_null_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_non_null_with_allocator(b) instead of b.into_non_null_with_allocator(). This is so that there is no conflict with a method on the inner type.

§Examples

Converting the NonNull pointer back into a Box with Box::from_non_null_in for automatic cleanup:

#![feature(allocator_api)]

use std::alloc::System;

let x = Box::new_in(String::from("Hello"), System);
let (non_null, alloc) = Box::into_non_null_with_allocator(x);
let x = unsafe { Box::from_non_null_in(non_null, alloc) };

Manual cleanup by explicitly running the destructor and deallocating the memory:

#![feature(allocator_api)]

use std::alloc::{Allocator, Layout, System};

let x = Box::new_in(String::from("Hello"), System);
let (non_null, alloc) = Box::into_non_null_with_allocator(x);
unsafe {
    non_null.drop_in_place();
    alloc.deallocate(non_null.cast::<u8>(), Layout::new::<String>());
}

pub fn as_mut_ptr(b: &mut Box<T, A>) -> *mut T

🔬This is a nightly-only experimental API. (box_as_ptr)

Returns a raw mutable pointer to the Box’s contents.

The caller must ensure that the Box outlives the pointer this function returns, or else it will end up dangling.

This method guarantees that for the purpose of the aliasing model, this method does not materialize a reference to the underlying memory, and thus the returned pointer will remain valid when mixed with other calls to as_ptr and as_mut_ptr. Note that calling other methods that materialize references to the memory may still invalidate this pointer. See the example below for how this guarantee can be used.

§Examples

Due to the aliasing guarantee, the following code is legal:

#![feature(box_as_ptr)]

unsafe {
    let mut b = Box::new(0);
    let ptr1 = Box::as_mut_ptr(&mut b);
    ptr1.write(1);
    let ptr2 = Box::as_mut_ptr(&mut b);
    ptr2.write(2);
    // Notably, the write to `ptr2` did *not* invalidate `ptr1`:
    ptr1.write(3);
}

pub fn as_ptr(b: &Box<T, A>) -> *const T

🔬This is a nightly-only experimental API. (box_as_ptr)

Returns a raw pointer to the Box’s contents.

The caller must ensure that the Box outlives the pointer this function returns, or else it will end up dangling.

The caller must also ensure that the memory the pointer (non-transitively) points to is never written to (except inside an UnsafeCell) using this pointer or any pointer derived from it. If you need to mutate the contents of the Box, use as_mut_ptr.

This method guarantees that for the purpose of the aliasing model, this method does not materialize a reference to the underlying memory, and thus the returned pointer will remain valid when mixed with other calls to as_ptr and as_mut_ptr. Note that calling other methods that materialize mutable references to the memory, as well as writing to this memory, may still invalidate this pointer. See the example below for how this guarantee can be used.

§Examples

Due to the aliasing guarantee, the following code is legal:

#![feature(box_as_ptr)]

unsafe {
    let mut v = Box::new(0);
    let ptr1 = Box::as_ptr(&v);
    let ptr2 = Box::as_mut_ptr(&mut v);
    let _val = ptr2.read();
    // No write to this memory has happened yet, so `ptr1` is still valid.
    let _val = ptr1.read();
    // However, once we do a write...
    ptr2.write(1);
    // ... `ptr1` is no longer valid.
    // This would be UB: let _val = ptr1.read();
}

pub fn allocator(b: &Box<T, A>) -> &A

🔬This is a nightly-only experimental API. (allocator_api)

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 · Source

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

Unsized 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]);

1.63.0 · Source

pub fn into_pin(boxed: Box<T, A>) -> Pin<Box<T, A>>
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);

Converts a type to a byte slice for the given mime type if possible.

1.5.0 · Source§

impl<T, A> AsMut<T> for Box<T, A>
where A: Allocator, T: ?Sized,

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

Converts this type into a mutable reference of the (usually inferred) input type.

1.63.0 · Source§

impl<T> AsRawFd for Box<T>
where T: AsRawFd,

fn as_raw_fd(&self) -> i32

Extracts the raw file descriptor. Read more

impl<T> AsRawXcbConnection for Box<T>
where T: AsRawXcbConnection + ?Sized,

Available on crate feature alloc only.

impl<T> AsyncBufRead for Box<T>
where T: AsyncBufRead + Unpin + ?Sized,

fn poll_fill_buf( self: Pin<&mut Box<T>>, cx: &mut Context<'_>, ) -> Poll<Result<&[u8], Error>>

Attempts to return the contents of the internal buffer, filling it with more data from the inner reader if it is empty. Read more

fn consume(self: Pin<&mut Box<T>>, amt: usize)

impl<Args, F, A> AsyncFnOnce<Args> for Box<F, A>
where Args: Tuple, F: AsyncFnOnce<Args> + ?Sized, A: Allocator,

type Output = <F as AsyncFnOnce<Args>>::Output

🔬This is a nightly-only experimental API. (async_fn_traits)

Output type of the called closure’s future.

type CallOnceFuture = <F as AsyncFnOnce<Args>>::CallOnceFuture

🔬This is a nightly-only experimental API. (async_fn_traits)

Future returned by AsyncFnOnce::async_call_once.

extern "rust-call" fn async_call_once( self, args: Args, ) -> <Box<F, A> as AsyncFnOnce<Args>>::CallOnceFuture

🔬This is a nightly-only experimental API. (async_fn_traits)

Call the AsyncFnOnce, returning a future which may move out of the called closure.

impl<S> AsyncIterator for Box<S>
where S: AsyncIterator + Unpin + ?Sized,

type Item = <S as AsyncIterator>::Item

🔬This is a nightly-only experimental API. (async_iterator)

The type of items yielded by the async iterator.

fn poll_next( self: Pin<&mut Box<S>>, cx: &mut Context<'_>, ) -> Poll<Option<<Box<S> as AsyncIterator>::Item>>

🔬This is a nightly-only experimental API. (async_iterator)

Attempts to pull out the next value of this async iterator, registering the current task for wakeup if the value is not yet available, and returning None if the async iterator is exhausted. Read more

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

🔬This is a nightly-only experimental API. (async_iterator)

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

impl<T> AsyncRead for Box<T>
where T: AsyncRead + Unpin + ?Sized,

fn poll_read( self: Pin<&mut Box<T>>, cx: &mut Context<'_>, buf: &mut [u8], ) -> Poll<Result<usize, Error>>

Attempt to read from the AsyncRead into buf. Read more

Waits for a seek operation to complete. Read more

impl<T> AsyncWrite for Box<T>
where T: AsyncWrite + Unpin + ?Sized,

fn poll_write( self: Pin<&mut Box<T>>, cx: &mut Context<'_>, buf: &[u8], ) -> Poll<Result<usize, Error>>

Attempt to write bytes from buf into the object. Read more

fn poll_write_vectored( self: Pin<&mut Box<T>>, cx: &mut Context<'_>, bufs: &[IoSlice<'_>], ) -> Poll<Result<usize, Error>>

Attempt to write bytes from bufs into the object using vectored IO operations. Read more

fn poll_flush( self: Pin<&mut Box<T>>, cx: &mut Context<'_>, ) -> Poll<Result<(), Error>>

Attempt to flush the object, ensuring that any buffered data reach their destination. Read more

fn poll_close( self: Pin<&mut Box<T>>, cx: &mut Context<'_>, ) -> Poll<Result<(), Error>>

Attempt to close the object. Read more

const SIGNATURE_CHAR: char = T::SIGNATURE_CHAR

The type signature, as a character.

const SIGNATURE_STR: &'static str = T::SIGNATURE_STR

The type signature, as a string.

fn alignment(format: Format) -> usize

The required padding alignment for the given format. Read more

impl<T> Basic for Box<T>
where T: Basic + ?Sized,

const SIGNATURE_CHAR: char = T::SIGNATURE_CHAR

The type signature, as a character.

const SIGNATURE_STR: &'static str = T::SIGNATURE_STR

The type signature, as a string.

Returns a slice starting at the current position and of length between 0 and Buf::remaining(). Note that this can return a shorter slice (this allows non-continuous internal representation). Read more

fn chunks_vectored<'b>(&'b self, dst: &mut [IoSlice<'b>]) -> usize

Available on crate feature std only.

Available on crate feature std only.

Creates an adaptor which implements the Read trait for self. Read more

Creates an adaptor which can write at most limit bytes to self. Read more

fn writer(self) -> Writer<Self>
where Self: Sized,

Available on crate feature std only.

Creates an adaptor which implements the Write trait for self. Read more

fn chain_mut(self, next: U) -> Chain<Self, U>
where U: BufMut, Self: Sized,

Creates an adapter which will chain this buffer with another. Read more

1.0.0 · Source§

impl BufRead for Box
where B: BufRead + ?Sized,

fn fill_buf(&mut self) -> Result<&[u8], Error>

Returns the contents of the internal buffer, filling it with more data, via Read methods, if empty. Read more

fn consume(&mut self, amt: usize)

Marks the given amount of additional bytes from the internal buffer as having been read. Subsequent calls to read only return bytes that have not been marked as read. Read more

fn has_data_left(&mut self) -> Result<bool, Error>

🔬This is a nightly-only experimental API. (buf_read_has_data_left)

Available on non-no_global_oom_handling only.

fn clone_from(&mut self, source: &Box<[T], A>)

Copies source’s contents into self without creating a new allocation, so long as the two are of the same length.

§Examples

let x = Box::new([5, 6, 7]);
let mut y = Box::new([8, 9, 10]);
let yp: *const [i32] = &*y;

y.clone_from(&x);

// The value is the same
assert_eq!(x, y);

// And no allocation occurred
assert_eq!(yp, &*y);

fn clone(&self) -> Box<[T], A>

Returns a duplicate of the value. Read more

impl Clone for Box<BStr>

impl<T, A> Clone for Box<T, A>
where T: Clone, A: Allocator + Clone,

Available on non-no_global_oom_handling only.

fn clone(&self) -> Box<T, A>

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

§Examples

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

// The value is the same
assert_eq!(x, y);

// But they are unique objects
assert_ne!(&*x as *const i32, &*y as *const i32);

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

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

§Examples

let x = Box::new(5);
let mut y = Box::new(10);
let yp: *const i32 = &*y;

y.clone_from(&x);

// The value is the same
assert_eq!(x, y);

// And no allocation occurred
assert_eq!(yp, &*y);

impl Clone for Box<dyn DynDigest>

Available on crate feature alloc only.

fn clone(&self) -> Box<dyn DynDigest>

Returns a duplicate of the value. Read more

1.0.0 · Source§

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

Performs copy-assignment from source. Read more

1.3.0 · Source§

impl Clone for Box<str>

Available on non-no_global_oom_handling only.

fn clone(&self) -> Box<str>

Returns a duplicate of the value. Read more

1.0.0 · Source§

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

Performs copy-assignment from source. Read more

Generate an error reply message for the given method call.

fn name(&self) -> ErrorName<'_>

The name of the error. Read more

fn description(&self) -> Option<&str>

The optional description for the error.

1.0.0 · Source§

impl<T, A> Debug for Box<T, A>
where T: Debug + ?Sized, A: Allocator,

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

Formats the value using the given formatter. Read more

1.0.0 · Source§

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

Available on non-no_global_oom_handling only.

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

Creates an empty [T] inside a Box.

impl Default for Box<BStr>

Available on crate feature alloc only.

type Target = T

The resulting type after dereferencing.

fn deref(&self) -> &T

Dereferences the value.

1.0.0 · Source§

fn deserialize<D>( deserializer: D, ) -> Result<Box<RawValue>, <D as Deserializer<'de>>::Error>
where D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer. Read more

impl<'de, T> Deserialize<'de> for Box<T>
where T: Deserialize<'de>,

Available on crate features std or alloc only.

fn deserialize<D>( deserializer: D, ) -> Result<Box<T>, <D as Deserializer<'de>>::Error>
where D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer. Read more

impl<'de> Deserialize<'de> for Box<str>

Available on crate features std or alloc only.

Available on crate feature alloc only.

Returns the nth element from the end of the iterator. Read more

fn advance_back_by(&mut self, n: usize) -> Result<(), NonZero<usize>>

🔬This is a nightly-only experimental API. (iter_advance_by)

Advances the iterator from the back by n elements. Read more

1.27.0 · Source§

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

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

1.27.0 · Source§

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

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

1.27.0 · Source§

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

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

1.0.0 · Source§

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

👎Deprecated since 1.33.0:

replaced by Error::source, which can support downcasting

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

Returns the lower-level source of this error, if any. Read more

fn provide<'b>(&'b self, request: &mut Request<'b>)

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

impl<Args, F, A> Fn<Args> for Box<F, A>
where Args: Tuple, F: Fn<Args> + ?Sized, A: Allocator,

extern "rust-call" fn call( &self, args: Args, ) -> <Box<F, A> as FnOnce<Args>>::Output

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

Performs the call operation.

extern "rust-call" fn call_once( self, args: Args, ) -> <Box<F, A> as FnOnce<Args>>::Output

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

Performs the call operation.

1.17.0 · Source§

impl<T> From<&[T]> for Box<[T]>
where T: Clone,

Available on non-no_global_oom_handling only.

fn from(slice: &[T]) -> Box<[T]>

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:?}");

1.17.0 · Source§

impl From<&CStr> for Box<CStr>

fn from(s: &CStr) -> Box<CStr>

Converts a &CStr into a Box<CStr>, by copying the contents into a newly allocated Box.

1.17.0 · Source§

impl From<&OsStr> for Box<OsStr>

fn from(s: &OsStr) -> Box<OsStr>

Copies the string into a newly allocated Box<OsStr>.

impl<T> From<&Slice<T>> for Box<Slice<T>>
where T: Copy,

fn from(slice: &Slice<T>) -> Box<Slice<T>>

Converts to this type from the input type.

1.84.0 · Source§

impl<T> From<&mut [T]> for Box<[T]>
where T: Clone,

Available on non-no_global_oom_handling only.

fn from(slice: &mut [T]) -> Box<[T]>

Converts a &mut [T] into a Box<[T]>

This conversion allocates on the heap and performs a copy of slice and its contents.

§Examples

// create a &mut [u8] which will be used to create a Box<[u8]>
let mut array = [104, 101, 108, 108, 111];
let slice: &mut [u8] = &mut array;
let boxed_slice: Box<[u8]> = Box::from(slice);

println!("{boxed_slice:?}");

This will allocate and clone path to it.

1.84.0 · Source§

impl From<&mut str> for Box<str>

Available on non-no_global_oom_handling only.

fn from(s: &mut str) -> Box<str>

Converts a &mut str into a Box<str>

This conversion allocates on the heap and performs a copy of s.

§Examples

let mut original = String::from("hello");
let original: &mut str = &mut original;
let boxed: Box<str> = Box::from(original);
println!("{boxed}");

1.6.0 · Source§

impl<'a> From<&str> for Box<dyn Error + 'a>

Available on non-no_global_oom_handling only.

fn from(err: &str) -> Box<dyn Error + 'a>

Converts a str into a box of dyn Error.

§Examples

use std::error::Error;

let a_str_error = "a str error";
let a_boxed_error = Box::<dyn Error>::from(a_str_error);
assert!(size_of::<Box<dyn Error>>() == size_of_val(&a_boxed_error))

1.0.0 · Source§

impl<'a> From<&str> for Box<dyn Error + Sync + Send + 'a>

Available on non-no_global_oom_handling only.

fn from(err: &str) -> Box<dyn Error + Sync + Send + 'a>

Converts a str into a box of dyn Error + Send + Sync.

§Examples

use std::error::Error;

let a_str_error = "a str error";
let a_boxed_error = Box::<dyn Error + Send + Sync>::from(a_str_error);
assert!(
    size_of::<Box<dyn Error + Send + Sync>>() == size_of_val(&a_boxed_error))

1.18.0 · Source§

impl<T, A> From<Box<[T], A>> for Vec<T, A>
where A: Allocator,

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

Converts a boxed slice into a vector by transferring ownership of the existing heap allocation.

§Examples

let b: Box<[i32]> = vec![1, 2, 3].into_boxed_slice();
assert_eq!(Vec::from(b), vec![1, 2, 3]);

Available on crate feature alloc only.

fn from(color: Box<Alpha<C, T>>) -> Box<[T; N]>

Converts to this type from the input type.

impl From<Box<BStr>> for Box<[u8]>

Available on crate feature alloc only.

fn from(raw_value: Box<RawValue>) -> Box<str>

Converts to this type from the input type.

impl<S, T> From<Box<Rgb<S, T>>> for Box<[T; 3]>

Available on crate feature alloc only.

fn from(color: Box<Rgb<S, T>>) -> Box<[T; 3]>

Converts to this type from the input type.

1.21.0 · Source§

impl<T, A> From<Box<T, A>> for Arc<T, A>
where A: Allocator, T: ?Sized,

Available on non-no_global_oom_handling only.

fn from(v: Box<T, A>) -> Arc<T, A> ⓘ

Move a boxed object to a new, reference-counted allocation.

§Example

let unique: Box<str> = Box::from("eggplant");
let shared: Arc<str> = Arc::from(unique);
assert_eq!("eggplant", &shared[..]);

1.33.0 · Source§

impl<T, A> From<Box<T, A>> for Pin<Box<T, A>>
where A: Allocator + 'static, T: ?Sized,

fn from(boxed: Box<T, A>) -> Pin<Box<T, A>>

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.

1.21.0 · Source§

impl<T, A> From<Box<T, A>> for Rc<T, A>
where A: Allocator, T: ?Sized,

Available on non-no_global_oom_handling only.

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

Move a boxed object to a new, reference counted, allocation.

§Example

let original: Box<i32> = Box::new(1);
let shared: Rc<i32> = Rc::from(original);
assert_eq!(1, *shared);

impl<Wp, T> From<Box<Xyz<Wp, T>>> for Box<[T; 3]>

Available on crate feature alloc only.

fn from(color: Box<Xyz<Wp, T>>) -> Box<[T; 3]>

Converts to this type from the input type.

impl<Wp, T> From<Box<Yxy<Wp, T>>> for Box<[T; 3]>

Available on crate feature alloc only.

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

Converts the given boxed str slice to a String. It is notable that the str slice is owned.

§Examples

let s1: String = String::from("hello world");
let s2: Box<str> = s1.into_boxed_str();
let s3: String = String::from(s2);

assert_eq!("hello world", s3)

1.19.0 · Source§

impl<A> From<Box<str, A>> for Box<[u8], A>
where A: Allocator,

fn from(s: Box<str, A>) -> Box<[u8], A>

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);

1.20.0 · Source§

impl From<CString> for Box<CStr>

fn from(s: CString) -> Box<CStr>

Converts a CString into a Box<CStr> without copying or allocating.

1.45.0 · Source§

impl<T> From<Cow<'_, [T]>> for Box<[T]>
where T: Clone,

Available on non-no_global_oom_handling only.

fn from(cow: Cow<'_, [T]>) -> Box<[T]>

Converts a Cow<'_, [T]> into a Box<[T]>

Creates a boxed Path from a clone-on-write pointer.

Converting from a Cow::Owned does not clone or allocate.

1.45.0 · Source§

impl From<Cow<'_, str>> for Box<str>

Available on non-no_global_oom_handling only.

fn from(cow: Cow<'_, str>) -> Box<str>

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}");

let unboxed = Cow::Owned("hello".to_string());
let boxed: Box<str> = Box::from(unboxed);
println!("{boxed}");

1.22.0 · Source§

impl<'a, 'b> From<Cow<'b, str>> for Box<dyn Error + 'a>

Available on non-no_global_oom_handling only.

fn from(err: Cow<'b, str>) -> Box<dyn Error + 'a>

Converts a Cow into a box of dyn Error.

§Examples

use std::error::Error;
use std::borrow::Cow;

let a_cow_str_error = Cow::from("a str error");
let a_boxed_error = Box::<dyn Error>::from(a_cow_str_error);
assert!(size_of::<Box<dyn Error>>() == size_of_val(&a_boxed_error))

1.22.0 · Source§

impl<'a, 'b> From<Cow<'b, str>> for Box<dyn Error + Sync + Send + 'a>

Available on non-no_global_oom_handling only.

fn from(err: Cow<'b, str>) -> Box<dyn Error + Sync + Send + 'a>

Converts a Cow into a box of dyn Error + Send + Sync.

§Examples

use std::error::Error;
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!(
    size_of::<Box<dyn Error + Send + Sync>>() == size_of_val(&a_boxed_error))

1.0.0 · Source§

impl<'a, E> From<E> for Box<dyn Error + 'a>
where E: Error + 'a,

Available on non-no_global_oom_handling only.

fn from(err: E) -> Box<dyn Error + 'a>

Converts a type of Error into a box of dyn Error.

§Examples

use std::error::Error;
use std::fmt;

#[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 == size_of_val(&an_error));
let a_boxed_error = Box::<dyn Error>::from(an_error);
assert!(size_of::<Box<dyn Error>>() == size_of_val(&a_boxed_error))

impl<'a> From<String> for Box<dyn Error + 'a>

Available on non-no_global_oom_handling only.

fn from(str_err: String) -> Box<dyn Error + 'a>

Converts a String into a box of dyn Error.

§Examples

use std::error::Error;

let a_string_error = "a string error".to_string();
let a_boxed_error = Box::<dyn Error>::from(a_string_error);
assert!(size_of::<Box<dyn Error>>() == size_of_val(&a_boxed_error))

1.0.0 · Source§

impl<'a> From<String> for Box<dyn Error + Sync + Send + 'a>

Available on non-no_global_oom_handling only.

fn from(err: String) -> Box<dyn Error + Sync + Send + 'a>

Converts a String into a box of dyn Error + Send + Sync.

§Examples

use std::error::Error;

let a_string_error = "a string error".to_string();
let a_boxed_error = Box::<dyn Error + Send + Sync>::from(a_string_error);
assert!(
    size_of::<Box<dyn Error + Send + Sync>>() == size_of_val(&a_boxed_error))

Available on non-no_global_oom_handling only.

fn from(t: T) -> Box<T>

Converts a T into a Box<T>

The conversion allocates on the heap and moves t from the stack into it.

§Examples

let x = 5;
let boxed = Box::new(5);

assert_eq!(Box::from(x), boxed);

1.20.0 · Source§

impl<T, A> From<Vec<T, A>> for Box<[T], A>
where A: Allocator,

Available on non-no_global_oom_handling only.

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

Converts a vector into a boxed slice.

Before doing the conversion, this method discards excess capacity like Vec::shrink_to_fit.

§Examples

assert_eq!(Box::from(vec![1, 2, 3]), vec![1, 2, 3].into_boxed_slice());

Any excess capacity is removed:

let mut vec = Vec::with_capacity(10);
vec.extend([1, 2, 3]);

assert_eq!(Box::from(vec), vec![1, 2, 3].into_boxed_slice());

impl<'a, T, C, const N: usize> FromArrays<&'a Box<[[T; N]]>> for &'a [C]
where C: ArrayCast<Array = [T; N]>,

fn from_arrays(arrays: &'a Box<[[T; N]]>) -> &'a [C]

Cast a collection of arrays into an collection of colors.

impl<'a, T, C, const N: usize> FromArrays<&'a mut Box<[[T; N]]>> for &'a mut [C]
where C: ArrayCast<Array = [T; N]>,

fn from_arrays(arrays: &'a mut Box<[[T; N]]>) -> &'a mut [C]

Cast a collection of arrays into an collection of colors.

impl<T, C, const N: usize> FromArrays<Box<[[T; N]]>> for Box<[C]>
where C: ArrayCast<Array = [T; N]>,

Available on crate feature alloc only.

fn from_arrays(arrays: Box<[[T; N]]>) -> Box<[C]>

Available on crate feature alloc only.

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

impl<H> HasDisplayHandle for Box<H>
where H: HasDisplayHandle + ?Sized,

Available on crate feature alloc only.

fn display_handle(&self) -> Result<DisplayHandle<'_>, HandleError>

Get a handle to the display controller of the windowing system.

impl<H> HasWindowHandle for Box<H>
where H: HasWindowHandle + ?Sized,

Available on crate feature alloc only.

fn window_handle(&self) -> Result<WindowHandle<'_>, HandleError>

Get a handle to the window.

1.0.0 · Source§

impl<T, A> Hash for Box<T, A>
where T: Hash + ?Sized, A: Allocator,

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

Feeds this value into the given Hasher. Read more

1.3.0 · Source§

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

Feeds a slice of this type into the given Hasher. Read more

1.22.0 · Source§

Writes a single isize into this hasher.

fn write_length_prefix(&mut self, len: usize)

🔬This is a nightly-only experimental API. (hasher_prefixfree_extras)

Writes a length prefix into this hasher, as part of being prefix-free. Read more

fn write_str(&mut self, s: &str)

🔬This is a nightly-only experimental API. (hasher_prefixfree_extras)

Writes a single str into this hasher. Read more

Available on crate feature alloc only.

fn into_arrays(self) -> Box<[[T; N]]>

Cast this collection of colors into a collection of arrays.

fn into_uints(self) -> &'a mut [<C as UintCast>::Uint]

Cast this collection of colors into a collection of unsigned integers.

impl<C> IntoUints<Box<[<C as UintCast>::Uint]>> for Box<[C]>
where C: UintCast,

Available on crate feature alloc only.

fn into_uints(self) -> Box<[<C as UintCast>::Uint]>

Cast this collection of colors into a collection of unsigned integers.

1.0.0 · Source§

🔬This is a nightly-only experimental API. (iter_next_chunk)

Advances the iterator and returns an array containing the next N values. Read more

1.0.0 · Source§

fn count(self) -> usize
where Self: Sized,

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

fn advance_by(&mut self, n: usize) -> Result<(), NonZero<usize>>

🔬This is a nightly-only experimental API. (iter_advance_by)

Advances the iterator by n elements. Read more

1.28.0 · Source§

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

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

1.0.0 · Source§

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

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

1.0.0 · Source§

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

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

fn intersperse(self, separator: Self::Item) -> Intersperse<Self>
where Self: Sized, Self::Item: Clone,

🔬This is a nightly-only experimental API. (iter_intersperse)

Creates a new iterator which places a copy of separator between items of the original iterator. Read more

fn intersperse_with<G>(self, separator: G) -> IntersperseWith<Self, G>
where Self: Sized, G: FnMut() -> Self::Item,

🔬This is a nightly-only experimental API. (iter_intersperse)

fn fuse(self) -> Fuse<Self>
where Self: Sized,

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

1.0.0 · Source§

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

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

1.0.0 · Source§

fn by_ref(&mut self) -> &mut Self
where Self: Sized,

Creates a “by reference” adapter for this instance of Iterator. Read more

1.0.0 · Source§

fn collect(self) -> B
where B: FromIterator<Self::Item>, Self: Sized,

Transforms an iterator into a collection. Read more

fn try_collect( &mut self, ) -> <<Self::Item as Try>::Residual as Residual>::TryType
where Self: Sized, Self::Item: Try, <Self::Item as Try>::Residual: Residual, B: FromIterator<<Self::Item as Try>::Output>,

🔬This is a nightly-only experimental API. (iterator_try_collect)

Fallibly transforms an iterator into a collection, short circuiting if a failure is encountered. Read more

fn collect_into<E>(self, collection: &mut E) -> &mut E
where E: Extend<Self::Item>, Self: Sized,

🔬This is a nightly-only experimental API. (iter_collect_into)

Collects all the items from an iterator into a collection. Read more

1.0.0 · Source§

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

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

fn partition_in_place<'a, T, P>(self, predicate: P) -> usize
where T: 'a, Self: Sized + DoubleEndedIterator<Item = &'a mut T>, P: FnMut(&T) -> bool,

🔬This is a nightly-only experimental API. (iter_partition_in_place)

Reorders the elements of this iterator in-place according to the given predicate, such that all those that return true precede all those that return false. Returns the number of true elements found. Read more

fn is_partitioned(self, predicate: P) -> bool
where Self: Sized, P: FnMut(Self::Item) -> bool,

🔬This is a nightly-only experimental API. (iter_is_partitioned)

Checks if the elements of this iterator are partitioned according to the given predicate, such that all those that return true precede all those that return false. Read more

1.27.0 · Source§

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

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

1.27.0 · Source§

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

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

1.0.0 · Source§

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

Folds every element into an accumulator by applying an operation, returning the final result. Read more

1.51.0 · Source§

fn reduce<F>(self, f: F) -> Option<Self::Item>
where Self: Sized, F: FnMut(Self::Item, Self::Item) -> Self::Item,

Reduces the elements to a single one, by repeatedly applying a reducing operation. Read more

fn try_reduce<R>( &mut self, f: impl FnMut(Self::Item, Self::Item) -> R, ) -> <<R as Try>::Residual as Residual<Option<<R as Try>::Output>>>::TryType
where Self: Sized, R: Try<Output = Self::Item>, <R as Try>::Residual: Residual<Option<Self::Item>>,

🔬This is a nightly-only experimental API. (iterator_try_reduce)

Reduces the elements to a single one by repeatedly applying a reducing operation. If the closure returns a failure, the failure is propagated back to the caller immediately. Read more

1.0.0 · Source§

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

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

1.0.0 · Source§

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

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

1.0.0 · Source§

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

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

1.30.0 · Source§

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

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

fn try_find<R>( &mut self, f: impl FnMut(&Self::Item) -> R, ) -> <<R as Try>::Residual as Residual<Option<Self::Item>>>::TryType
where Self: Sized, R: Try<Output = bool>, <R as Try>::Residual: Residual<Option<Self::Item>>,

🔬This is a nightly-only experimental API. (try_find)

🔬This is a nightly-only experimental API. (iter_array_chunks)

Returns an iterator over N elements of the iterator at a time. Read more

1.11.0 · Source§

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

Sums the elements of an iterator. Read more

1.11.0 · Source§

Checks if the elements of this iterator are sorted using the given key extraction function. Read more

Flushes any buffered records. Read more

Used to mark the beginning of operations for a widget and its children

Used to mark the beginning of operations for a widget and its children

1.0.0 · Source§

impl<T, A> Ord for Box<T, A>
where T: Ord + ?Sized, A: Allocator,

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

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

1.21.0 · Source§

fn max(self, other: Self) -> Self
where Self: Sized,

Compares and returns the maximum of two values. Read more

1.21.0 · Source§

fn min(self, other: Self) -> Self
where Self: Sized,

Compares and returns the minimum of two values. Read more

1.50.0 · Source§

fn clamp(self, min: Self, max: Self) -> Self
where Self: Sized,

Restrict a value to a certain interval. Read more

impl<T> Parse for Box<T>
where T: Parse,

Convert the parser’s error to another type using std::convert::From

1.0.0 · Source§

impl<T, A> PartialEq for Box<T, A>
where T: PartialEq + ?Sized, A: Allocator,

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

Tests for self and other values to be equal, and is used by ==.

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

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

1.0.0 · Source§

🔬This is a nightly-only experimental API. (read_buf)

Pull some bytes from this source into the specified buffer. Read more

fn read_vectored(&mut self, bufs: &mut [IoSliceMut<'_>]) -> Result<usize, Error>

Like read, except that it reads into a slice of buffers. Read more

fn is_read_vectored(&self) -> bool

🔬This is a nightly-only experimental API. (can_vector)

Determines if this Reader has an efficient read_vectored implementation. Read more

fn read_to_end(&mut self, buf: &mut Vec<u8>) -> Result<usize, Error>

Reads all bytes until EOF in this source, placing them into buf. Read more

fn read_to_string(&mut self, buf: &mut String) -> Result<usize, Error>

Reads all bytes until EOF in this source, appending them to buf. Read more

fn read_exact(&mut self, buf: &mut [u8]) -> Result<(), Error>

Reads the exact number of bytes required to fill buf. Read more

fn read_buf_exact(&mut self, cursor: BorrowedCursor<'_>) -> Result<(), Error>

🔬This is a nightly-only experimental API. (read_buf)

Seek to an offset, in bytes, in a stream. Read more

fn rewind(&mut self) -> Result<(), Error>

Rewind to the beginning of a stream. Read more

fn stream_len(&mut self) -> Result<u64, Error>

🔬This is a nightly-only experimental API. (seek_stream_len)

Returns the length of this stream (in bytes). Read more

fn stream_position(&mut self) -> Result<u64, Error>

Returns the current seek position from the start of the stream. Read more

fn seek_relative(&mut self, offset: i64) -> Result<(), Error>

Seeks relative to the current position. Read more

impl<T> Serialize for Box<T>
where T: Serialize + ?Sized,

Available on crate features std or alloc only.

Available on crate feature alloc only.

Attempts to prepare the Sink to receive a value. Read more

fn start_send( self: Pin<&mut Box<S>>, item: Item, ) -> Result<(), <Box<S> as Sink<Item>>::Error>

Begin the process of sending a value to the sink. Each call to this function must be preceded by a successful call to poll_ready which returned Poll::Ready(Ok(())). Read more

fn poll_flush( self: Pin<&mut Box<S>>, cx: &mut Context<'_>, ) -> Poll<Result<(), <Box<S> as Sink<Item>>::Error>>

Flush any remaining output from this sink. Read more

fn poll_close( self: Pin<&mut Box<S>>, cx: &mut Context<'_>, ) -> Poll<Result<(), <Box<S> as Sink<Item>>::Error>>

Flush any remaining output and close this sink, if necessary. Read more

impl<T> Source for Box<T>
where T: Source + ?Sized,

fn register( &mut self, registry: &Registry, token: Token, interests: Interest, ) -> Result<(), Error>

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

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

Notifies the subscriber that a span ID has been dropped, and returns true if there are now 0 IDs that refer to that span. Read more

fn drop_span(&self, id: Id)

👎Deprecated since 0.1.2:

use Subscriber::try_close instead

This method is deprecated. Read more

fn current_span(&self) -> Current

Returns a type representing this subscriber’s view of the current span. Read more

unsafe fn downcast_raw(&self, id: TypeId) -> Option<*const ()>

If self is the same type as the provided TypeId, returns an untyped *const pointer to that type. Otherwise, returns None. Read more

fn on_register_dispatch(&self, subscriber: &Dispatch)

Invoked when this subscriber becomes a [Dispatch]. Read more

Returns the original Vec<T> in the Err variant if boxed_slice.len() does not equal N.

§Examples

This can be used with vec! to create an array on the heap:

let state: Box<[f32; 100]> = vec![1.0; 100].try_into().unwrap();
assert_eq!(state.len(), 100);

type Error = Vec<T>

The type returned in the event of a conversion error.

impl<'a, T, C> TryFromComponents<&'a Box<[T]>> for &'a [C]
where T: 'a, C: ArrayCast, <C as ArrayCast>::Array: ArrayExt<Item = T>,

type Error = SliceCastError

The error for when try_from_components fails to cast.

fn try_from_components( components: &'a Box<[T]>, ) -> Result<&'a [C], <&'a [C] as TryFromComponents<&'a Box<[T]>>>::Error>

Try to cast a collection of color components into an collection of colors. Read more

Like write, except that it writes from a slice of buffers. Read more

fn is_write_vectored(&self) -> bool

🔬This is a nightly-only experimental API. (can_vector)

Determines if this Writer has an efficient write_vectored implementation. Read more

fn flush(&mut self) -> Result<(), Error>

Flushes this output stream, ensuring that all intermediately buffered contents reach their destination. Read more

fn write_all(&mut self, buf: &[u8]) -> Result<(), Error>

Attempts to write an entire buffer into this writer. Read more

fn write_all_vectored(&mut self, bufs: &mut [IoSlice<'_>]) -> Result<(), Error>

🔬This is a nightly-only experimental API. (write_all_vectored)

Attempts to write multiple buffers into this writer. Read more

fn write_fmt(&mut self, fmt: Arguments<'_>) -> Result<(), Error>

Writes a formatted string into this writer, returning any error encountered. Read more

1.0.0 · Source§

fn by_ref(&mut self) -> &mut Self
where Self: Sized,

Creates a “by reference” adapter for this instance of Write. Read more

impl<T, A> DerefPure for Box<T, A>
where A: Allocator, T: ?Sized,

impl<T, U> DispatchFromDyn<Box> for Box<T>
where T: Unsize + ?Sized, U: ?Sized,

1.0.0 · Source§

impl<T, A> Eq for Box<T, A>
where T: Eq + ?Sized, A: Allocator,

impl<T> FromStream<T> for Box<[T]>

1.26.0 · Source§

impl<I, A> FusedIterator for Box<I, A>
where I: FusedIterator + ?Sized, A: Allocator,

impl<T> IoSafe for Box<T>
where T: IoSafe + ?Sized,

1.80.0 · Source§

impl<'a, I, A> !Iterator for &'a Box<[I], A>
where A: Allocator,

This implementation is required to make sure that the &Box<[I]>: IntoIterator implementation doesn’t overlap with IntoIterator for T where T: Iterator blanket.

1.80.0 · Source§

impl<'a, I, A> !Iterator for &'a mut Box<[I], A>
where A: Allocator,

This implementation is required to make sure that the &mut Box<[I]>: IntoIterator implementation doesn’t overlap with IntoIterator for T where T: Iterator blanket.

1.80.0 · Source§

impl<I, A> !Iterator for Box<[I], A>
where A: Allocator,

This implementation is required to make sure that the Box<[I]>: IntoIterator implementation doesn’t overlap with IntoIterator for T where T: Iterator blanket.

impl<T, A> UnwindSafe for Box<T, A>
where A: UnwindSafe, T: UnwindSafe + ?Sized,

Blanket Implementations§

👎Deprecated since 0.10.0:

use TryRng instead

Error type.

impl<T, A, P> Access<T> for P
where A: Access<T> + ?Sized, P: Deref<Target = A>,

type Guard = <A as Access<T>>::Guard

A guard object containing the value and keeping it alive. Read more

fn load(&self) -> >::Guard

The loading method. Read more

impl<T, C> AdaptIntoUnclamped<T> for C
where T: AdaptFromUnclamped<C>,

type Scalar = <T as AdaptFromUnclamped<C>>::Scalar

The number type that’s used as the color’s components.

fn adapt_into_unclamped_with<M>(self) -> T
where M: LmsToXyz<<C as AdaptIntoUnclamped<T>>::Scalar> + XyzToLms<<C as AdaptIntoUnclamped<T>>::Scalar>,

Adapt a color of type Self into a color of type T, using the custom matrix M. Read more

fn apply_ref<F>(&self, f: F) -> Res
where F: FnOnce(&Self) -> Res,

Apply a function which takes the parameter by reference.

Consumes amt buffered bytes. Read more

fn read_until<'a>( &'a mut self, byte: u8, buf: &'a mut Vec<u8>, ) -> ReadUntilFuture<'a, Self> ⓘ
where Self: Unpin,

Reads all bytes and appends them into buf until the delimiter byte or EOF is found. Read more

fn read_line<'a>(&'a mut self, buf: &'a mut String) -> ReadLineFuture<'a, Self> ⓘ
where Self: Unpin,

Reads all bytes and appends them into buf until a newline (the 0xA byte) or EOF is found. Read more

fn lines(self) -> Lines<Self>
where Self: Sized,

Returns a stream over the lines of this byte stream. Read more

fn split(self, byte: u8) -> Split<Self>
where Self: Sized,

Returns a stream over the contents of this reader split on the specified byte. Read more

Returns a stream over the lines of this reader. This method is the async equivalent to BufRead::lines. Read more

fn boxed_reader<'a>(self) -> Pin<Box<dyn AsyncRead + Send + 'a>>
where Self: Sized + Send + 'a,

Available on crate feature alloc only.

Boxes the reader and changes its type to dyn AsyncRead + Send + 'a. Read more

Creates a future which will rewind to the beginning of the stream. Read more

fn stream_position(&mut self) -> Seek<'_, Self>
where Self: Unpin,

Creates a future which will return the current seek position from the start of the stream. Read more

impl<S> AsyncSeekExt for S
where S: AsyncSeek + ?Sized,

fn seek(&mut self, pos: SeekFrom) -> Seek<'_, Self> ⓘ
where Self: Unpin,

Creates a future which will seek an IO object, and then yield the new position in the object and the object itself. Read more

fn stream_position(&mut self) -> Seek<'_, Self> ⓘ
where Self: Unpin,

Creates a future which will return the current seek position from the start of the stream. Read more

Available on crate feature alloc only.

Boxes the writer and changes its type to dyn AsyncWrite + Send + 'a. Read more

fn for_byte_line<F>(&mut self, for_each_line: F) -> Result<(), Error>
where Self: Sized, F: FnMut(&[u8]) -> Result<bool, Error>,

Executes the given closure on each line in the underlying reader. Read more

fn for_byte_record<F>( &mut self, terminator: u8, for_each_record: F, ) -> Result<(), Error>
where Self: Sized, F: FnMut(&[u8]) -> Result<bool, Error>,

Executes the given closure on each byte-terminated record in the underlying reader. Read more

fn for_byte_line_with_terminator<F>( &mut self, for_each_line: F, ) -> Result<(), Error>
where Self: Sized, F: FnMut(&[u8]) -> Result<bool, Error>,

Executes the given closure on each line in the underlying reader. Read more

fn for_byte_record_with_terminator<F>( &mut self, terminator: u8, for_each_record: F, ) -> Result<(), Error>
where Self: Sized, F: FnMut(&[u8]) -> Result<bool, Error>,

Executes the given closure on each byte-terminated record in the underlying reader. Read more

impl<WpParam, T, U> Cam16IntoUnclamped<WpParam, T> for U
where T: FromCam16Unclamped<WpParam, U>,

type Scalar = <T as FromCam16Unclamped<WpParam, U>>::Scalar

The number type that’s used in parameters when converting.

fn cam16_into_unclamped( self, parameters: BakedParameters<WpParam, >::Scalar>, ) -> T

Converts self into C, using the provided parameters.

Change window stacking order. Read more

fn get_geometry( &self, drawable: u32, ) -> Result<Cookie<'_, Self, GetGeometryReply>, ConnectionError>

Get current window geometry. Read more

fn query_tree( &self, window: u32, ) -> Result<Cookie<'_, Self, QueryTreeReply>, ConnectionError>

query the window tree. Read more

Gets the owner of a selection. Read more

fn convert_selection<A, B>( &self, requestor: u32, selection: u32, target: u32, property: A, time: B, ) -> Result<VoidCookie<'_, Self>, ConnectionError>
where A: Into<u32>, B: Into<u32>,

fn send_event<A, B>( &self, propagate: bool, destination: A, event_mask: EventMask, event: B, ) -> Result<VoidCookie<'_, Self>, ConnectionError>
where A: Into<u32>, B: Into<[u8; 32]>,

send an event. Read more

fn grab_pointer<A, B, C>( &self, owner_events: bool, grab_window: u32, event_mask: EventMask, pointer_mode: GrabMode, keyboard_mode: GrabMode, confine_to: A, cursor: B, time: C, ) -> Result<Cookie<'_, Self, GrabPointerReply>, ConnectionError>
where A: Into<u32>, B: Into<u32>, C: Into<u32>,

Grab the pointer. Read more

fn ungrab_pointer<A>( &self, time: A, ) -> Result<VoidCookie<'_, Self>, ConnectionError>
where A: Into<u32>,

release the pointer. Read more

fn grab_button<A, B>( &self, owner_events: bool, grab_window: u32, event_mask: EventMask, pointer_mode: GrabMode, keyboard_mode: GrabMode, confine_to: A, cursor: B, button: ButtonIndex, modifiers: ModMask, ) -> Result<VoidCookie<'_, Self>, ConnectionError>
where A: Into<u32>, B: Into<u32>,

Grab pointer button(s). Read more

fn ungrab_button( &self, button: ButtonIndex, grab_window: u32, modifiers: ModMask, ) -> Result<VoidCookie<'_, Self>, ConnectionError>

fn change_active_pointer_grab<A, B>( &self, cursor: A, time: B, event_mask: EventMask, ) -> Result<VoidCookie<'_, Self>, ConnectionError>
where A: Into<u32>, B: Into<u32>,

fn grab_keyboard<A>( &self, owner_events: bool, grab_window: u32, time: A, pointer_mode: GrabMode, keyboard_mode: GrabMode, ) -> Result<Cookie<'_, Self, GrabKeyboardReply>, ConnectionError>
where A: Into<u32>,

Grab the keyboard. Read more

fn ungrab_keyboard<A>( &self, time: A, ) -> Result<VoidCookie<'_, Self>, ConnectionError>
where A: Into<u32>,

fn grab_key<A>( &self, owner_events: bool, grab_window: u32, modifiers: ModMask, key: A, pointer_mode: GrabMode, keyboard_mode: GrabMode, ) -> Result<VoidCookie<'_, Self>, ConnectionError>
where A: Into<u8>,

Grab keyboard key(s). Read more

fn ungrab_key<A>( &self, key: A, grab_window: u32, modifiers: ModMask, ) -> Result<VoidCookie<'_, Self>, ConnectionError>
where A: Into<u8>,

release a key combination. Read more

fn allow_events<A>( &self, mode: Allow, time: A, ) -> Result<VoidCookie<'_, Self>, ConnectionError>
where A: Into<u32>,

release queued events. Read more

fn grab_server(&self) -> Result<VoidCookie<'_, Self>, ConnectionError>

opens a font. Read more

fn close_font(&self, font: u32) -> Result<VoidCookie<'_, Self>, ConnectionError>

fn query_font( &self, font: u32, ) -> Result<Cookie<'_, Self, QueryFontReply>, ConnectionError>

query font metrics. Read more

fn query_text_extents<'c, 'input>( &'c self, font: u32, string: &'input [Char2b], ) -> Result<Cookie<'c, Self, QueryTextExtentsReply>, ConnectionError>

get text extents. Read more

fn list_fonts<'c, 'input>( &'c self, max_names: u16, pattern: &'input [u8], ) -> Result<Cookie<'c, Self, ListFontsReply>, ConnectionError>

get matching font names. Read more

fn list_fonts_with_info<'c, 'input>( &'c self, max_names: u16, pattern: &'input [u8], ) -> Result<ListFontsWithInfoCookie<'c, Self>, ConnectionError>

get matching font names and information. Read more

fn set_font_path<'c, 'input>( &'c self, font: &'input [Str], ) -> Result<VoidCookie<'c, Self>, ConnectionError>

fn get_font_path( &self, ) -> Result<Cookie<'_, Self, GetFontPathReply>, ConnectionError>

fn create_pixmap( &self, depth: u8, pid: u32, drawable: u32, width: u16, height: u16, ) -> Result<VoidCookie<'_, Self>, ConnectionError>

Creates a pixmap. Read more

fn free_pixmap( &self, pixmap: u32, ) -> Result<VoidCookie<'_, Self>, ConnectionError>

Destroys a pixmap. Read more

fn create_gc<'c, 'input>( &'c self, cid: u32, drawable: u32, value_list: &'input CreateGCAux, ) -> Result<VoidCookie<'c, Self>, ConnectionError>

Creates a graphics context. Read more

fn change_gc<'c, 'input>( &'c self, gc: u32, value_list: &'input ChangeGCAux, ) -> Result<VoidCookie<'c, Self>, ConnectionError>

change graphics context components. Read more

fn copy_gc( &self, src_gc: u32, dst_gc: u32, value_mask: GC, ) -> Result<VoidCookie<'_, Self>, ConnectionError>

fn poly_line<'c, 'input>( &'c self, coordinate_mode: CoordMode, drawable: u32, gc: u32, points: &'input [Point], ) -> Result<VoidCookie<'c, Self>, ConnectionError>

draw lines. Read more

fn poly_segment<'c, 'input>( &'c self, drawable: u32, gc: u32, segments: &'input [Segment], ) -> Result<VoidCookie<'c, Self>, ConnectionError>

draw lines. Read more

fn poly_rectangle<'c, 'input>( &'c self, drawable: u32, gc: u32, rectangles: &'input [Rectangle], ) -> Result<VoidCookie<'c, Self>, ConnectionError>

fn poly_arc<'c, 'input>( &'c self, drawable: u32, gc: u32, arcs: &'input [Arc], ) -> Result<VoidCookie<'c, Self>, ConnectionError>

fn fill_poly<'c, 'input>( &'c self, drawable: u32, gc: u32, shape: PolyShape, coordinate_mode: CoordMode, points: &'input [Point], ) -> Result<VoidCookie<'c, Self>, ConnectionError>

fn poly_fill_rectangle<'c, 'input>( &'c self, drawable: u32, gc: u32, rectangles: &'input [Rectangle], ) -> Result<VoidCookie<'c, Self>, ConnectionError>

Fills rectangles. Read more

Draws text. Read more

fn image_text16<'c, 'input>( &'c self, drawable: u32, gc: u32, x: i16, y: i16, string: &'input [Char2b], ) -> Result<VoidCookie<'c, Self>, ConnectionError>

Draws text. Read more

fn free_cursor( &self, cursor: u32, ) -> Result<VoidCookie<'_, Self>, ConnectionError>

Deletes a cursor. Read more

fn recolor_cursor( &self, cursor: u32, fore_red: u16, fore_green: u16, fore_blue: u16, back_red: u16, back_green: u16, back_blue: u16, ) -> Result<VoidCookie<'_, Self>, ConnectionError>

fn query_best_size( &self, class: QueryShapeOf, drawable: u32, width: u16, height: u16, ) -> Result<Cookie<'_, Self, QueryBestSizeReply>, ConnectionError>

fn query_extension<'c, 'input>( &'c self, name: &'input [u8], ) -> Result<Cookie<'c, Self, QueryExtensionReply>, ConnectionError>

check if extension is present. Read more

Enable the BIG-REQUESTS extension. Read more

impl<T> Downcast for T
where T: Any,

fn into_any(self: Box<T>) -> Box<dyn Any>

Convert Box<dyn Trait> (where Trait: Downcast) to Box<dyn Any>. Box<dyn Any> can then be further downcast into Box<ConcreteType> where ConcreteType implements Trait.

fn into_any_rc(self: Rc<T>) -> Rc<dyn Any>

Convert Rc<Trait> (where Trait: Downcast) to Rc<Any>. Rc<Any> can then be further downcast into Rc<ConcreteType> where ConcreteType implements Trait.

fn as_any(&self) -> &(dyn Any + 'static)

Convert &Trait (where Trait: Downcast) to &Any. This is needed since Rust cannot generate &Any’s vtable from &Trait’s.

Get a deserializer compatible with this parsed signature.

impl<'de, T> DynamicDeserialize<'de> for T
where T: Type + Deserialize<'de>,

type Deserializer = PhantomData<T>

impl<F> FutureExt for F
where F: Future + ?Sized,

fn poll(&mut self, cx: &mut Context<'_>) -> Poll<Self::Output>
where Self: Unpin,

A convenience for calling Future::poll() on !Unpin types.

Turns a Future<Output = T> into a TryFuture<Ok = T, Error = ()>.

fn never_error(self) -> NeverError<Self> ⓘ
where Self: Sized,

Turns a Future<Output = T> into a TryFuture<Ok = T, Error = Never>.

fn poll_unpin(&mut self, cx: &mut Context<'_>) -> Poll<Self::Output>
where Self: Unpin,

A convenience for calling Future::poll on Unpin future types.

fn now_or_never(self) -> Option<Self::Output>
where Self: Sized,

Evaluates and consumes the future, returning the resulting output if the future is ready after the first call to Future::poll. Read more

impl<T> Instrument for T

fn instrument(self, span: Span) -> Instrumented<Self> ⓘ

Instruments this type with the provided [Span], returning an Instrumented wrapper. Read more

fn in_current_span(self) -> Instrumented<Self> ⓘ

Instruments this type with the current Span, returning an Instrumented wrapper. Read more

impl IntoAsyncIterator for I
where I: AsyncIterator,

type Item = ::Item

🔬This is a nightly-only experimental API. (async_iterator)

The type of the item yielded by the iterator

type IntoAsyncIter = I

🔬This is a nightly-only experimental API. (async_iterator)

The type of the resulting iterator

fn into_async_iter(self) -> ::IntoAsyncIter

🔬This is a nightly-only experimental API. (async_iterator)

type IntoFuture = F

Which kind of future are we turning this into?

fn into_future(self) -> <F as IntoFuture>::IntoFuture

Creates a future from a value. Read more

impl IntoIterator for I
where I: Iterator,

type Item = ::Item

The type of the elements being iterated over.

type IntoIter = I

Which kind of iterator are we turning this into?

Uniformly sample one element (stable) Read more

fn sample_fill<R>(self, rng: &mut R, buf: &mut [Self::Item]) -> usize
where R: Rng + ?Sized,

Uniformly sample amount distinct elements into a buffer Read more

fn sample<R>(self, rng: &mut R, amount: usize) -> Vec<Self::Item>
where R: Rng + ?Sized,

Available on crate feature alloc only.

Uniformly sample amount distinct elements into a Vec Read more

fn choose_multiple_fill<R>(self, rng: &mut R, buf: &mut [Self::Item]) -> usize
where R: Rng + ?Sized,

👎Deprecated since 0.10.0:

Renamed to sample_fill

Deprecated: use [Self::sample_fill] instead

fn choose_multiple<R>(self, rng: &mut R, amount: usize) -> Vec<Self::Item>
where R: Rng + ?Sized,

👎Deprecated since 0.10.0:

Renamed to sample

Available on crate feature alloc only.

Deprecated: use [Self::sample] instead

The none-equivalent value.

impl<T> NoneValue for T
where T: Default,

type NoneType = T

The type of the none-equivalent value that [NoneValue::null_value] produces.

fn null_value() -> T

The none-equivalent value.

type Output = T

fn parse2(self, tokens: TokenStream) -> Result<T, Error>

Parse a proc-macro2 token stream into the chosen syntax tree node. Read more

fn __parse_scoped( self, scope: Span, tokens: TokenStream, ) -> Result<<F as Parser>::Output, Error>

fn parse(self, tokens: TokenStream) -> Result<Self::Output, Error>

Available on crate feature proc-macro only.

Parse tokens of source code into the chosen syntax tree node. Read more

fn parse_str(self, s: &str) -> Result<Self::Output, Error>

Parse a string of Rust code into the chosen syntax tree node. Read more

impl<Iter> PathIterator for Iter
where Iter: Iterator<Item = Event<Point2D<f32, UnknownUnit>, Point2D<f32, UnknownUnit>>>,

fn flattened(self, tolerance: f32) -> Flattened<Self> ⓘ

Returns an iterator that turns curves into line segments.

fn transformed<T>(self, mat: &T) -> Transformed<'_, Self, T> ⓘ
where T: Transformation<f32>,

Returns an iterator applying a 2D transform to all of its events.

🔬This is a nightly-only experimental API. (pattern)

Returns the pattern as utf-8 bytes if possible.

Read a f64.

Reads a IEEE754 double-precision (8 bytes) floating point number from the underlying reader. Read more

Composes a function in front of the sink. Read more

fn sink_map_err<E, F>(self, f: F) -> SinkMapErr<Self, F>
where F: FnOnce(Self::Error) -> E, Self: Sized,

Transforms the error returned by the sink.

fn sink_err_into<E>(self) -> SinkErrInto<Self, Item, E>
where Self: Sized, Self::Error: Into<E>,

Map this sink’s error to a different error type using the Into trait. Read more

fn buffer(self, capacity: usize) -> Buffer<Self, Item>
where Self: Sized,

Available on crate feature alloc only.

A convenience method for calling Sink::poll_close on Unpin sink types.

impl<T> Spanned for T
where T: Spanned + ?Sized,

fn span(&self) -> Span

Returns a Span covering the complete contents of this syntax tree node, or Span::call_site() if this node is empty.

fn race<S>(self, other: S) -> Race<Self, S>
where Self: Sized, S: Stream<Item = Self::Item>,

Available on crate features std and race only.

Merges with other stream, with no preference for either stream when both are ready. Read more

Turns the stream into a peekable stream, whose next element can be peeked at without being consumed. Read more

Flattens a stream of streams into just one continuous stream. Read more

fn flatten_unordered( self, limit: impl Into<Option<usize>>, ) -> FlattenUnorderedWithFlowController<Self, ()>
where Self::Item: Stream + Unpin, Self: Sized,

Available on target_has_atomic=ptr and crate feature alloc only.

Flattens a stream of streams into just one continuous stream. Polls inner streams produced by the base stream concurrently. Read more

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

Maps a stream like StreamExt::map but flattens nested Streams. Read more

fn flat_map_unordered<U, F>( self, limit: impl Into<Option<usize>>, f: F, ) -> FlatMapUnordered<Self, U, F>
where U: Stream + Unpin, F: FnMut(Self::Item) -> U, Self: Sized,

Available on target_has_atomic=ptr and crate feature alloc only.

Available on target_has_atomic=ptr and crate feature alloc only.

Runs this stream to completion, executing the provided asynchronous closure for each element on the stream concurrently as elements become available. Read more

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

Creates a new stream of at most n items of the underlying stream. Read more

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

Creates a new stream which skips n items of the underlying stream. Read more

fn fuse(self) -> Fuse<Self>
where Self: Sized,

Fuse a stream such that poll_next will never again be called once it has finished. This method can be used to turn any Stream into a FusedStream. Read more

An adapter for zipping two streams together. Read more

fn chain<St>(self, other: St) -> Chain<Self, St>
where St: Stream<Item = Self::Item>, Self: Sized,

Adapter for chaining two streams. Read more

Do something with each item of this stream, afterwards passing it on. Read more

fn left_stream(self) -> Either<Self, B> ⓘ
where B: Stream<Item = Self::Item>, Self: Sized,

Wrap this stream in an Either stream, making it the left-hand variant of that Either. Read more

fn right_stream(self) -> Either<B, Self> ⓘ
where B: Stream<Item = Self::Item>, Self: Sized,

Wrap this stream in an Either stream, making it the right-hand variant of that Either. Read more

fn poll_next_unpin(&mut self, cx: &mut Context<'_>) -> Poll<Option<Self::Item>>
where Self: Unpin,

A convenience method for calling Stream::poll_next on Unpin stream types.

Encode the hex strict representing self into the result. Upper case letters are used (e.g. F9B4CA)

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

type Owned = T

The resulting type after obtaining ownership.

fn to_owned(&self) -> T

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

fn clone_into(&self, target: &mut T)

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

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

fn to_smolstr(&self) -> SmolStr

The type returned in the event of a conversion error.

Return the next random u32.

fn try_next_u64(&mut self) -> Result<u64, <R as TryRng>::Error>

Return the next random u64.

fn try_fill_bytes(&mut self, dst: &mut [u8]) -> Result<(), <R as TryRng>::Error>

Fill dst entirely with random data.

impl<S, T, E> TryStream for S
where S: Stream<Item = Result<T, E>> + ?Sized,

type Ok = T

The type of successful values yielded by this future

type Error = E

The type of failures yielded by this future

fn try_poll_next( self: Pin<&mut S>, cx: &mut Context<'_>, ) -> Poll<Option<Result<<S as TryStream>::Ok, <S as TryStream>::Error>>>

Poll this TryStream as if it were a Stream. Read more

Take elements on this stream while the provided asynchronous predicate resolves to true. Read more

fn try_for_each_concurrent<Fut, F>( self, limit: impl Into<Option<usize>>, f: F, ) -> TryForEachConcurrent<Self, Fut, F> ⓘ
where F: FnMut(Self::Ok) -> Fut, Fut: Future<Output = Result<(), Self::Error>>, Self: Sized,

Available on target_has_atomic=ptr and crate feature alloc only.

Attempts to run this stream to completion, executing the provided asynchronous closure for each element on the stream concurrently as elements become available, exiting as soon as an error occurs. Read more

Attempt to filter the values produced by this stream according to the provided asynchronous closure. Read more

fn try_filter_map<Fut, F, T>(self, f: F) -> TryFilterMap<Self, Fut, F>
where Fut: TryFuture<Ok = Option<T>, Error = Self::Error>, F: FnMut(Self::Ok) -> Fut, Self: Sized,

Attempt to filter the values produced by this stream while simultaneously mapping them to a different type according to the provided asynchronous closure. Read more

fn try_flatten_unordered( self, limit: impl Into<Option<usize>>, ) -> TryFlattenUnordered<Self>
where Self::Ok: TryStream + Unpin, <Self::Ok as TryStream>::Error: From<Self::Error>, Self: Sized,

Available on target_has_atomic=ptr and crate feature alloc only.

Flattens a stream of streams into just one continuous stream. Produced streams will be polled concurrently and any errors will be passed through without looking at them. If the underlying base stream returns an error, it will be immediately propagated. Read more

fn try_flatten(self) -> TryFlatten<Self>
where Self::Ok: TryStream, <Self::Ok as TryStream>::Error: From<Self::Error>, Self: Sized,

Flattens a stream of streams into just one continuous stream. Read more

fn try_fold<T, Fut, F>(self, init: T, f: F) -> TryFold<Self, Fut, T, F> ⓘ
where F: FnMut(T, Self::Ok) -> Fut, Fut: TryFuture<Ok = T, Error = Self::Error>, Self: Sized,

Attempt to execute an accumulating asynchronous computation over a stream, collecting all the values into one final result. Read more

A convenience method for calling TryStream::try_poll_next on Unpin stream types.

fn into_async_read(self) -> IntoAsyncRead<Self>
where Self: Sized + TryStreamExt<Error = Error>, Self::Ok: AsRef<[u8]>,

Available on crate features io and std only.

Adapter that converts this stream into an AsyncBufRead. Read more

fn try_all<Fut, F>(self, f: F) -> TryAll<Self, Fut, F> ⓘ
where Self: Sized, F: FnMut(Self::Ok) -> Fut, Fut: Future<Output = bool>,

Attempt to execute a predicate over an asynchronous stream and evaluate if all items satisfy the predicate. Exits early if an Err is encountered or if an Ok item is found that does not satisfy the predicate. Read more

Available on crate feature std only.

Records a type implementing Error. Read more

impl<T> WithSubscriber for T

fn with_subscriber<S>(self, subscriber: S) -> WithDispatch<Self> ⓘ
where S: Into<Dispatch>,

Attaches the provided Subscriber to this type, returning a [WithDispatch] wrapper. Read more

fn with_current_subscriber(self) -> WithDispatch<Self> ⓘ

Attaches the current default Subscriber to this type, returning a [WithDispatch] wrapper. Read more

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