Struct std::boxed::Box
pub struct Box<T, A = Global>(_, _) where T: ?Sized, A: Allocator;
A pointer type for heap allocation.
See the module-level documentation for more.
Implementations
impl<T> Box<T, Global>
pub fn new(x: T) -> Box<T, Global>
impl<I, A> Iterator for Box<I, A> where I: Iterator + ?Sized, A: Allocator, type Item = <I as Iterator>::Item; impl<F, A> Future for Box<F, A> where F: Future + Unpin + ?Sized, A: Allocator + 'static, type Output = <F as Future>::Output; impl<R: Read + ?Sized> Read for Box<R> impl<W: Write + ?Sized> Write for Box<W>
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);
pub fn new_uninit() -> Box<MaybeUninit<T>, Global>
impl<I, A> Iterator for Box<I, A> where I: Iterator + ?Sized, A: Allocator, type Item = <I as Iterator>::Item; impl<F, A> Future for Box<F, A> where F: Future + Unpin + ?Sized, A: Allocator + 'static, type Output = <F as Future>::Output; impl<R: Read + ?Sized> Read for Box<R> impl<W: Write + ?Sized> Write for Box<W>
Constructs a new box with uninitialized contents.
Examples
#![feature(new_uninit)] let mut five = Box::<u32>::new_uninit(); let five = unsafe { // Deferred initialization: five.as_mut_ptr().write(5); five.assume_init() }; assert_eq!(*five, 5)
pub fn new_zeroed() -> Box<MaybeUninit<T>, Global>
impl<I, A> Iterator for Box<I, A> where I: Iterator + ?Sized, A: Allocator, type Item = <I as Iterator>::Item; impl<F, A> Future for Box<F, A> where F: Future + Unpin + ?Sized, A: Allocator + 'static, type Output = <F as Future>::Output; impl<R: Read + ?Sized> Read for Box<R> impl<W: Write + ?Sized> Write for Box<W>
Constructs a new Box
with uninitialized contents, with the memory being filled with 0
bytes.
See MaybeUninit::zeroed
for examples of correct and incorrect usage of this method.
Examples
#![feature(new_uninit)] let zero = Box::<u32>::new_zeroed(); let zero = unsafe { zero.assume_init() }; assert_eq!(*zero, 0)
pub fn pin(x: T) -> Pin<Box<T, Global>>
impl<P> Future for Pin<P> where P: DerefMut, <P as Deref>::Target: Future, type Output = <<P as Deref>::Target as Future>::Output;
Constructs a new Pin<Box<T>>
. If T
does not implement Unpin
, then x
will be pinned in memory and unable to be moved.
pub fn try_new(x: T) -> Result<Box<T, Global>, AllocError>
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>, Global>, AllocError>
Constructs a new box with uninitialized contents on the heap, returning an error if the allocation fails
Examples
#![feature(allocator_api, new_uninit)] let mut five = Box::<u32>::try_new_uninit()?; let five = unsafe { // Deferred initialization: five.as_mut_ptr().write(5); five.assume_init() }; assert_eq!(*five, 5);
pub fn try_new_zeroed() -> Result<Box<MaybeUninit<T>, Global>, AllocError>
Constructs a new Box
with uninitialized contents, with the memory being filled with 0
bytes on the heap
See MaybeUninit::zeroed
for examples of correct and incorrect usage of this method.
Examples
#![feature(allocator_api, new_uninit)] let zero = Box::<u32>::try_new_zeroed()?; let zero = unsafe { zero.assume_init() }; assert_eq!(*zero, 0);
pub fn new_in(x: T, alloc: A) -> Box<T, A>
impl<I, A> Iterator for Box<I, A> where I: Iterator + ?Sized, A: Allocator, type Item = <I as Iterator>::Item; impl<F, A> Future for Box<F, A> where F: Future + Unpin + ?Sized, A: Allocator + 'static, type Output = <F as Future>::Output; impl<R: Read + ?Sized> Read for Box<R> impl<W: Write + ?Sized> Write for Box<W>
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>
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>
impl<I, A> Iterator for Box<I, A> where I: Iterator + ?Sized, A: Allocator, type Item = <I as Iterator>::Item; impl<F, A> Future for Box<F, A> where F: Future + Unpin + ?Sized, A: Allocator + 'static, type Output = <F as Future>::Output; impl<R: Read + ?Sized> Read for Box<R> impl<W: Write + ?Sized> Write for Box<W>
Constructs a new box with uninitialized contents in the provided allocator.
Examples
#![feature(allocator_api, new_uninit)] use std::alloc::System; let mut five = Box::<u32, _>::new_uninit_in(System); let five = unsafe { // Deferred initialization: five.as_mut_ptr().write(5); five.assume_init() }; assert_eq!(*five, 5)
pub fn try_new_uninit_in(alloc: A) -> Result<Box<MaybeUninit<T>, A>, AllocError>
Constructs a new box with uninitialized contents in the provided allocator, returning an error if the allocation fails
Examples
#![feature(allocator_api, new_uninit)] use std::alloc::System; let mut five = Box::<u32, _>::try_new_uninit_in(System)?; let five = unsafe { // Deferred initialization: five.as_mut_ptr().write(5); five.assume_init() }; assert_eq!(*five, 5);
pub fn new_zeroed_in(alloc: A) -> Box<MaybeUninit<T>, A>
impl<I, A> Iterator for Box<I, A> where I: Iterator + ?Sized, A: Allocator, type Item = <I as Iterator>::Item; impl<F, A> Future for Box<F, A> where F: Future + Unpin + ?Sized, A: Allocator + 'static, type Output = <F as Future>::Output; impl<R: Read + ?Sized> Read for Box<R> impl<W: Write + ?Sized> Write for Box<W>
Constructs a new Box
with uninitialized contents, with the memory being filled with 0
bytes in the provided allocator.
See MaybeUninit::zeroed
for examples of correct and incorrect usage of this method.
Examples
#![feature(allocator_api, new_uninit)] use std::alloc::System; let zero = Box::<u32, _>::new_zeroed_in(System); let zero = unsafe { zero.assume_init() }; assert_eq!(*zero, 0)
pub fn try_new_zeroed_in(alloc: A) -> Result<Box<MaybeUninit<T>, A>, AllocError>
Constructs a new Box
with uninitialized contents, with the memory being filled with 0
bytes in the provided allocator, returning an error if the allocation fails,
See MaybeUninit::zeroed
for examples of correct and incorrect usage of this method.
Examples
#![feature(allocator_api, new_uninit)] use std::alloc::System; let zero = Box::<u32, _>::try_new_zeroed_in(System)?; let zero = unsafe { zero.assume_init() }; assert_eq!(*zero, 0);
pub fn pin_in(x: T, alloc: A) -> Pin<Box<T, A>> where
A: 'static,
impl<P> Future for Pin<P> where P: DerefMut, <P as Deref>::Target: Future, type Output = <<P as Deref>::Target as Future>::Output;
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.
pub fn into_boxed_slice(boxed: Box<T, A>) -> Box<[T], A>
impl<I, A> Iterator for Box<I, A> where I: Iterator + ?Sized, A: Allocator, type Item = <I as Iterator>::Item; impl<F, A> Future for Box<F, A> where F: Future + Unpin + ?Sized, A: Allocator + 'static, type Output = <F as Future>::Output; impl<R: Read + ?Sized> Read for Box<R> impl<W: Write + ?Sized> Write for Box<W>
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
Consumes the Box
, returning the wrapped value.
Examples
#![feature(box_into_inner)] let c = Box::new(5); assert_eq!(Box::into_inner(c), 5);
impl<T> Box<[T], Global>
pub fn new_uninit_slice(len: usize) -> Box<[MaybeUninit<T>], Global>
impl<I, A> Iterator for Box<I, A> where I: Iterator + ?Sized, A: Allocator, type Item = <I as Iterator>::Item; impl<F, A> Future for Box<F, A> where F: Future + Unpin + ?Sized, A: Allocator + 'static, type Output = <F as Future>::Output; impl<R: Read + ?Sized> Read for Box<R> impl<W: Write + ?Sized> Write for Box<W>
Constructs a new boxed slice with uninitialized contents.
Examples
#![feature(new_uninit)] let mut values = Box::<[u32]>::new_uninit_slice(3); let values = unsafe { // Deferred initialization: values[0].as_mut_ptr().write(1); values[1].as_mut_ptr().write(2); values[2].as_mut_ptr().write(3); values.assume_init() }; assert_eq!(*values, [1, 2, 3])
pub fn new_zeroed_slice(len: usize) -> Box<[MaybeUninit<T>], Global>
impl<I, A> Iterator for Box<I, A> where I: Iterator + ?Sized, A: Allocator, type Item = <I as Iterator>::Item; impl<F, A> Future for Box<F, A> where F: Future + Unpin + ?Sized, A: Allocator + 'static, type Output = <F as Future>::Output; impl<R: Read + ?Sized> Read for Box<R> impl<W: Write + ?Sized> Write for Box<W>
Constructs a new boxed slice with uninitialized contents, with the memory being filled with 0
bytes.
See MaybeUninit::zeroed
for examples of correct and incorrect usage of this method.
Examples
#![feature(new_uninit)] let values = Box::<[u32]>::new_zeroed_slice(3); let values = unsafe { values.assume_init() }; assert_eq!(*values, [0, 0, 0])
pub fn try_new_uninit_slice(
len: usize
) -> Result<Box<[MaybeUninit<T>], Global>, AllocError>
Constructs a new boxed slice with uninitialized contents. Returns an error if the allocation fails
Examples
#![feature(allocator_api, new_uninit)] let mut values = Box::<[u32]>::try_new_uninit_slice(3)?; let values = unsafe { // Deferred initialization: values[0].as_mut_ptr().write(1); values[1].as_mut_ptr().write(2); values[2].as_mut_ptr().write(3); values.assume_init() }; assert_eq!(*values, [1, 2, 3]);
pub fn try_new_zeroed_slice(
len: usize
) -> Result<Box<[MaybeUninit<T>], Global>, AllocError>
Constructs a new boxed slice with uninitialized contents, with the memory being filled with 0
bytes. Returns an error if the allocation fails
See MaybeUninit::zeroed
for examples of correct and incorrect usage of this method.
Examples
#![feature(allocator_api, new_uninit)] let values = Box::<[u32]>::try_new_zeroed_slice(3)?; let values = unsafe { values.assume_init() }; assert_eq!(*values, [0, 0, 0]);
pub fn new_uninit_slice_in(len: usize, alloc: A) -> Box<[MaybeUninit<T>], A>
impl<I, A> Iterator for Box<I, A> where I: Iterator + ?Sized, A: Allocator, type Item = <I as Iterator>::Item; impl<F, A> Future for Box<F, A> where F: Future + Unpin + ?Sized, A: Allocator + 'static, type Output = <F as Future>::Output; impl<R: Read + ?Sized> Read for Box<R> impl<W: Write + ?Sized> Write for Box<W>
Constructs a new boxed slice with uninitialized contents in the provided allocator.
Examples
#![feature(allocator_api, new_uninit)] use std::alloc::System; let mut values = Box::<[u32], _>::new_uninit_slice_in(3, System); let values = unsafe { // Deferred initialization: values[0].as_mut_ptr().write(1); values[1].as_mut_ptr().write(2); values[2].as_mut_ptr().write(3); values.assume_init() }; assert_eq!(*values, [1, 2, 3])
pub fn new_zeroed_slice_in(len: usize, alloc: A) -> Box<[MaybeUninit<T>], A>
impl<I, A> Iterator for Box<I, A> where I: Iterator + ?Sized, A: Allocator, type Item = <I as Iterator>::Item; impl<F, A> Future for Box<F, A> where F: Future + Unpin + ?Sized, A: Allocator + 'static, type Output = <F as Future>::Output; impl<R: Read + ?Sized> Read for Box<R> impl<W: Write + ?Sized> Write for Box<W>
Constructs a new boxed slice with uninitialized contents in the provided allocator, with the memory being filled with 0
bytes.
See MaybeUninit::zeroed
for examples of correct and incorrect usage of this method.
Examples
#![feature(allocator_api, new_uninit)] use std::alloc::System; let values = Box::<[u32], _>::new_zeroed_slice_in(3, System); let values = unsafe { values.assume_init() }; assert_eq!(*values, [0, 0, 0])
pub unsafe fn assume_init(self) -> Box<T, A>
impl<I, A> Iterator for Box<I, A> where I: Iterator + ?Sized, A: Allocator, type Item = <I as Iterator>::Item; impl<F, A> Future for Box<F, A> where F: Future + Unpin + ?Sized, A: Allocator + 'static, type Output = <F as Future>::Output; impl<R: Read + ?Sized> Read for Box<R> impl<W: Write + ?Sized> Write for Box<W>
Converts to Box<T, A>
.
Safety
As with MaybeUninit::assume_init
, it is up to the caller to guarantee that the value really is in an initialized state. Calling this when the content is not yet fully initialized causes immediate undefined behavior.
Examples
#![feature(new_uninit)] let mut five = Box::<u32>::new_uninit(); let five: Box<u32> = unsafe { // Deferred initialization: five.as_mut_ptr().write(5); five.assume_init() }; assert_eq!(*five, 5)
pub unsafe fn assume_init(self) -> Box<[T], A>
impl<I, A> Iterator for Box<I, A> where I: Iterator + ?Sized, A: Allocator, type Item = <I as Iterator>::Item; impl<F, A> Future for Box<F, A> where F: Future + Unpin + ?Sized, A: Allocator + 'static, type Output = <F as Future>::Output; impl<R: Read + ?Sized> Read for Box<R> impl<W: Write + ?Sized> Write for Box<W>
Converts to Box<[T], A>
.
Safety
As with MaybeUninit::assume_init
, it is up to the caller to guarantee that the values really are in an initialized state. Calling this when the content is not yet fully initialized causes immediate undefined behavior.
Examples
#![feature(new_uninit)] let mut values = Box::<[u32]>::new_uninit_slice(3); let values = unsafe { // Deferred initialization: values[0].as_mut_ptr().write(1); values[1].as_mut_ptr().write(2); values[2].as_mut_ptr().write(3); values.assume_init() }; assert_eq!(*values, [1, 2, 3])
pub unsafe fn from_raw(raw: *mut T) -> Box<T, Global>
impl<I, A> Iterator for Box<I, A> where I: Iterator + ?Sized, A: Allocator, type Item = <I as Iterator>::Item; impl<F, A> Future for Box<F, A> where F: Future + Unpin + ?Sized, A: Allocator + 'static, type Output = <F as Future>::Output; impl<R: Read + ?Sized> Read for Box<R> impl<W: Write + ?Sized> Write for Box<W>
Constructs a box from a raw pointer.
After calling this function, the raw pointer is owned by the resulting Box
. Specifically, the Box
destructor will call the destructor of T
and free the allocated memory. For this to be safe, the memory must have been allocated in accordance with the memory layout used by Box
.
Safety
This function is unsafe because improper use may lead to memory problems. For example, a double-free may occur if the function is called twice on the same raw pointer.
The safety conditions are described in the memory layout section.
Examples
Recreate a Box
which was previously converted to a raw pointer using Box::into_raw
:
let x = Box::new(5); let ptr = Box::into_raw(x); let x = unsafe { Box::from_raw(ptr) };
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_raw_in(raw: *mut T, alloc: A) -> Box<T, A>
impl<I, A> Iterator for Box<I, A> where I: Iterator + ?Sized, A: Allocator, type Item = <I as Iterator>::Item; impl<F, A> Future for Box<F, A> where F: Future + Unpin + ?Sized, A: Allocator + 'static, type Output = <F as Future>::Output; impl<R: Read + ?Sized> Read for Box<R> impl<W: Write + ?Sized> Write for Box<W>
Constructs a box from a raw pointer in the given allocator.
After calling this function, the raw pointer is owned by the resulting Box
. Specifically, the Box
destructor will call the destructor of T
and free the allocated memory. For this to be safe, the memory must have been allocated in accordance with the memory layout used by Box
.
Safety
This function is unsafe because improper use may lead to memory problems. For example, a double-free may occur if the function is called twice on the same raw pointer.
Examples
Recreate a Box
which was previously converted to a raw pointer using Box::into_raw_with_allocator
:
#![feature(allocator_api)] use std::alloc::System; let x = Box::new_in(5, System); let (ptr, alloc) = Box::into_raw_with_allocator(x); let x = unsafe { Box::from_raw_in(ptr, alloc) };
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 fn into_raw(b: Box<T, A>) -> *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 p = Box::into_raw(x); unsafe { ptr::drop_in_place(p); dealloc(p as *mut u8, Layout::new::<String>()); }
pub fn into_raw_with_allocator(b: Box<T, A>) -> (*mut T, A)
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 allocator(b: &Box<T, A>) -> &A
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.
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]);
pub fn into_pin(boxed: Box<T, A>) -> Pin<Box<T, A>> where
A: 'static,
impl<P> Future for Pin<P> where P: DerefMut, <P as Deref>::Target: Future, type Output = <<P as Deref>::Target as Future>::Output;
Converts a Box<T>
into a Pin<Box<T>>
This conversion does not allocate on the heap and happens in place.
This is also available via From
.
Attempt to downcast the box to a concrete type.
Examples
use std::any::Any; fn print_if_string(value: Box<dyn Any>) { if let Ok(string) = value.downcast::<String>() { println!("String ({}): {}", string.len(), string); } } let my_string = "Hello World".to_string(); print_if_string(Box::new(my_string)); print_if_string(Box::new(0i8));
Attempt to downcast the box to a concrete type.
Examples
use std::any::Any; fn print_if_string(value: Box<dyn Any + Send>) { if let Ok(string) = value.downcast::<String>() { println!("String ({}): {}", string.len(), string); } } let my_string = "Hello World".to_string(); print_if_string(Box::new(my_string)); print_if_string(Box::new(0i8));
Attempt to downcast the box to a concrete type.
Examples
use std::any::Any; fn print_if_string(value: Box<dyn Any + Send + Sync>) { if let Ok(string) = value.downcast::<String>() { println!("String ({}): {}", string.len(), string); } } let my_string = "Hello World".to_string(); print_if_string(Box::new(my_string)); print_if_string(Box::new(0i8));
Trait Implementations
pub fn as_mut(&mut self) -> &mut T
Performs the conversion.
pub fn as_ref(&self) -> &T
Performs the conversion.
impl<B: BufRead + ?Sized> BufRead for Box<B>
fn fill_buf(&mut self) -> Result<&[u8]>
Returns the contents of the internal buffer, filling it with more data from the inner reader if it is empty. Read more
fn consume(&mut self, amt: usize)
Tells this buffer that amt
bytes have been consumed from the buffer, so they should no longer be returned in calls to read
. Read more
fn read_until(&mut self, byte: u8, buf: &mut Vec<u8>) -> Result<usize>
Read all bytes into buf
until the delimiter byte
or EOF is reached. Read more
fn read_line(&mut self, buf: &mut String) -> Result<usize>
Read all bytes until a newline (the 0xA
byte) is reached, and append them to the provided buffer. Read more
fn has_data_left(&mut self) -> Result<bool>
buf_read_has_data_left
#86423)recently added
Check if the underlying Read
has any data left to be read. Read more
impl<B: BufRead> Iterator for Split<B> type Item = Result<Vec<u8>>;
Returns an iterator over the contents of this reader split on the byte byte
. Read more
impl<B: BufRead> Iterator for Lines<B> type Item = Result<String>;
Returns an iterator over the lines of this reader. Read more
pub fn clone(&self) -> Box<[T], A>
impl<I, A> Iterator for Box<I, A> where I: Iterator + ?Sized, A: Allocator, type Item = <I as Iterator>::Item; impl<F, A> Future for Box<F, A> where F: Future + Unpin + ?Sized, A: Allocator + 'static, type Output = <F as Future>::Output; impl<R: Read + ?Sized> Read for Box<R> impl<W: Write + ?Sized> Write for Box<W>
Returns a copy of the value. Read more
pub fn clone_from(&mut self, other: &Box<[T], A>)
Performs copy-assignment from source
. Read more
impl Clone for Box<str, Global>
pub fn clone(&self) -> Box<str, Global>
impl<I, A> Iterator for Box<I, A> where I: Iterator + ?Sized, A: Allocator, type Item = <I as Iterator>::Item; impl<F, A> Future for Box<F, A> where F: Future + Unpin + ?Sized, A: Allocator + 'static, type Output = <F as Future>::Output; impl<R: Read + ?Sized> Read for Box<R> impl<W: Write + ?Sized> Write for Box<W>
Returns a copy of the value. Read more
fn clone_from(&mut self, source: &Self)
Performs copy-assignment from source
. Read more
pub fn clone(&self) -> Box<T, A>
impl<I, A> Iterator for Box<I, A> where I: Iterator + ?Sized, A: Allocator, type Item = <I as Iterator>::Item; impl<F, A> Future for Box<F, A> where F: Future + Unpin + ?Sized, A: Allocator + 'static, type Output = <F as Future>::Output; impl<R: Read + ?Sized> Read for Box<R> impl<W: Write + ?Sized> Write for Box<W>
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);
pub 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<CStr>
fn clone(&self) -> Self
Returns a copy of the value. Read more
fn clone_from(&mut self, source: &Self)
Performs copy-assignment from source
. Read more
impl Clone for Box<OsStr>
fn clone(&self) -> Self
Returns a copy of the value. Read more
fn clone_from(&mut self, source: &Self)
Performs copy-assignment from source
. Read more
impl Clone for Box<Path>
fn clone(&self) -> Self
Returns a copy of the value. Read more
fn clone_from(&mut self, source: &Self)
Performs copy-assignment from source
. Read more
pub fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>
Formats the value using the given formatter. Read more
impl Default for Box<str, Global>
pub fn default() -> Box<str, Global>
impl<I, A> Iterator for Box<I, A> where I: Iterator + ?Sized, A: Allocator, type Item = <I as Iterator>::Item; impl<F, A> Future for Box<F, A> where F: Future + Unpin + ?Sized, A: Allocator + 'static, type Output = <F as Future>::Output; impl<R: Read + ?Sized> Read for Box<R> impl<W: Write + ?Sized> Write for Box<W>
Returns the “default value” for a type. Read more
pub fn default() -> Box<T, Global>
impl<I, A> Iterator for Box<I, A> where I: Iterator + ?Sized, A: Allocator, type Item = <I as Iterator>::Item; impl<F, A> Future for Box<F, A> where F: Future + Unpin + ?Sized, A: Allocator + 'static, type Output = <F as Future>::Output; impl<R: Read + ?Sized> Read for Box<R> impl<W: Write + ?Sized> Write for Box<W>
Creates a Box<T>
, with the Default
value for T.
impl<T> Default for Box<[T], Global>
pub fn default() -> Box<[T], Global>
impl<I, A> Iterator for Box<I, A> where I: Iterator + ?Sized, A: Allocator, type Item = <I as Iterator>::Item; impl<F, A> Future for Box<F, A> where F: Future + Unpin + ?Sized, A: Allocator + 'static, type Output = <F as Future>::Output; impl<R: Read + ?Sized> Read for Box<R> impl<W: Write + ?Sized> Write for Box<W>
Returns the “default value” for a type. Read more
impl Default for Box<CStr>
fn default() -> Box<CStr>
impl<I, A> Iterator for Box<I, A> where I: Iterator + ?Sized, A: Allocator, type Item = <I as Iterator>::Item; impl<F, A> Future for Box<F, A> where F: Future + Unpin + ?Sized, A: Allocator + 'static, type Output = <F as Future>::Output; impl<R: Read + ?Sized> Read for Box<R> impl<W: Write + ?Sized> Write for Box<W>
Returns the “default value” for a type. Read more
impl Default for Box<OsStr>
fn default() -> Box<OsStr>
impl<I, A> Iterator for Box<I, A> where I: Iterator + ?Sized, A: Allocator, type Item = <I as Iterator>::Item; impl<F, A> Future for Box<F, A> where F: Future + Unpin + ?Sized, A: Allocator + 'static, type Output = <F as Future>::Output; impl<R: Read + ?Sized> Read for Box<R> impl<W: Write + ?Sized> Write for Box<W>
Returns the “default value” for a type. Read more
type Target = T
The resulting type after dereferencing.
pub fn deref(&self) -> &T
Dereferences the value.
pub fn deref_mut(&mut self) -> &mut T
Mutably dereferences the value.
pub fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>
Formats the value using the given formatter. Read more
impl<I, A> DoubleEndedIterator for Box<I, A> where
I: DoubleEndedIterator + ?Sized,
A: Allocator,
pub fn next_back(&mut self) -> Option<<I as Iterator>::Item>
Removes and returns an element from the end of the iterator. Read more
pub fn nth_back(&mut self, n: usize) -> Option<<I as Iterator>::Item>
Returns the n
th element from the end of the iterator. Read more
fn advance_back_by(&mut self, n: usize) -> Result<(), usize>
iter_advance_by
#77404)recently added
Advances the iterator from the back by n
elements. Read more
This is the reverse version of Iterator::try_fold()
: it takes elements starting from the back of the iterator. Read more
An iterator method that reduces the iterator’s elements to a single, final value, starting from the back. Read more
Searches for an element of an iterator from the back that satisfies a predicate. Read more
impl<T: Error> Error for Box<T>
fn description(&self) -> &str
use the Display impl or to_string()
fn cause(&self) -> Option<&dyn Error>
replaced by Error::source, which can support downcasting
fn source(&self) -> Option<&(dyn Error + 'static)>
The lower-level source of this error, if any. Read more
fn backtrace(&self) -> Option<&Backtrace>
Returns a stack backtrace, if available, of where this error occurred. Read more
impl<I, A> ExactSizeIterator for Box<I, A> where
I: ExactSizeIterator + ?Sized,
A: Allocator,
pub fn len(&self) -> usize
Returns the exact length of the iterator. Read more
pub fn is_empty(&self) -> bool
Returns true
if the iterator is empty. Read more
impl Extend<Box<str, Global>> for String
pub fn extend<I>(&mut self, iter: I) where
I: IntoIterator<Item = Box<str, Global>>,
Extends a collection with the contents of an iterator. Read more
fn extend_one(&mut self, item: A)
Extends a collection with exactly one element.
fn extend_reserve(&mut self, additional: usize)
Reserves capacity in a collection for the given number of additional elements. Read more
pub extern "rust-call" fn call(
&self,
args: Args
) -> <Box<F, A> as FnOnce<Args>>::Output
impl<I, A> Iterator for Box<I, A> where I: Iterator + ?Sized, A: Allocator, type Item = <I as Iterator>::Item; impl<F, A> Future for Box<F, A> where F: Future + Unpin + ?Sized, A: Allocator + 'static, type Output = <F as Future>::Output; impl<R: Read + ?Sized> Read for Box<R> impl<W: Write + ?Sized> Write for Box<W>
Performs the call operation.
pub extern "rust-call" fn call_mut(
&mut self,
args: Args
) -> <Box<F, A> as FnOnce<Args>>::Output
impl<I, A> Iterator for Box<I, A> where I: Iterator + ?Sized, A: Allocator, type Item = <I as Iterator>::Item; impl<F, A> Future for Box<F, A> where F: Future + Unpin + ?Sized, A: Allocator + 'static, type Output = <F as Future>::Output; impl<R: Read + ?Sized> Read for Box<R> impl<W: Write + ?Sized> Write for Box<W>
Performs the call operation.
type Output = <F as FnOnce<Args>>::Output
The returned type after the call operator is used.
pub extern "rust-call" fn call_once(
self,
args: Args
) -> <Box<F, A> as FnOnce<Args>>::Output
impl<I, A> Iterator for Box<I, A> where I: Iterator + ?Sized, A: Allocator, type Item = <I as Iterator>::Item; impl<F, A> Future for Box<F, A> where F: Future + Unpin + ?Sized, A: Allocator + 'static, type Output = <F as Future>::Output; impl<R: Read + ?Sized> Read for Box<R> impl<W: Write + ?Sized> Write for Box<W>
Performs the call operation.
pub fn from(slice: &[T]) -> Box<[T], Global>
impl<I, A> Iterator for Box<I, A> where I: Iterator + ?Sized, A: Allocator, type Item = <I as Iterator>::Item; impl<F, A> Future for Box<F, A> where F: Future + Unpin + ?Sized, A: Allocator + 'static, type Output = <F as Future>::Output; impl<R: Read + ?Sized> Read for Box<R> impl<W: Write + ?Sized> Write for Box<W>
Converts a &[T]
into a Box<[T]>
This conversion allocates on the heap and performs a copy of slice
.
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);
impl From<&'_ CStr> for Box<CStr>
fn from(s: &CStr) -> Box<CStr>
impl<I, A> Iterator for Box<I, A> where I: Iterator + ?Sized, A: Allocator, type Item = <I as Iterator>::Item; impl<F, A> Future for Box<F, A> where F: Future + Unpin + ?Sized, A: Allocator + 'static, type Output = <F as Future>::Output; impl<R: Read + ?Sized> Read for Box<R> impl<W: Write + ?Sized> Write for Box<W>
Performs the conversion.
impl From<&'_ OsStr> for Box<OsStr>
fn from(s: &OsStr) -> Box<OsStr>
impl<I, A> Iterator for Box<I, A> where I: Iterator + ?Sized, A: Allocator, type Item = <I as Iterator>::Item; impl<F, A> Future for Box<F, A> where F: Future + Unpin + ?Sized, A: Allocator + 'static, type Output = <F as Future>::Output; impl<R: Read + ?Sized> Read for Box<R> impl<W: Write + ?Sized> Write for Box<W>
Performs the conversion.
impl From<&'_ Path> for Box<Path>
fn from(path: &Path) -> Box<Path>
impl<I, A> Iterator for Box<I, A> where I: Iterator + ?Sized, A: Allocator, type Item = <I as Iterator>::Item; impl<F, A> Future for Box<F, A> where F: Future + Unpin + ?Sized, A: Allocator + 'static, type Output = <F as Future>::Output; impl<R: Read + ?Sized> Read for Box<R> impl<W: Write + ?Sized> Write for Box<W>
Creates a boxed Path
from a reference.
This will allocate and clone path
to it.
impl<'_> From<&'_ str> for Box<str, Global>
pub fn from(s: &str) -> Box<str, Global>
impl<I, A> Iterator for Box<I, A> where I: Iterator + ?Sized, A: Allocator, type Item = <I as Iterator>::Item; impl<F, A> Future for Box<F, A> where F: Future + Unpin + ?Sized, A: Allocator + 'static, type Output = <F as Future>::Output; impl<R: Read + ?Sized> Read for Box<R> impl<W: Write + ?Sized> Write for Box<W>
Converts a &str
into a Box<str>
This conversion allocates on the heap and performs a copy of s
.
Examples
let boxed: Box<str> = Box::from("hello"); println!("{}", boxed);
impl<'a> From<&'_ str> for Box<dyn Error + Send + Sync + 'a>
fn from(err: &str) -> Box<dyn Error + Send + Sync + 'a>
impl<I, A> Iterator for Box<I, A> where I: Iterator + ?Sized, A: Allocator, type Item = <I as Iterator>::Item; impl<F, A> Future for Box<F, A> where F: Future + Unpin + ?Sized, A: Allocator + 'static, type Output = <F as Future>::Output; impl<R: Read + ?Sized> Read for Box<R> impl<W: Write + ?Sized> Write for Box<W>
impl From<&'_ str> for Box<dyn Error>
fn from(err: &str) -> Box<dyn Error>
impl<I, A> Iterator for Box<I, A> where I: Iterator + ?Sized, A: Allocator, type Item = <I as Iterator>::Item; impl<F, A> Future for Box<F, A> where F: Future + Unpin + ?Sized, A: Allocator + 'static, type Output = <F as Future>::Output; impl<R: Read + ?Sized> Read for Box<R> impl<W: Write + ?Sized> Write for Box<W>
impl<T, const N: usize> From<[T; N]> for Box<[T], Global>
pub fn from(array: [T; N]) -> Box<[T], Global>
impl<I, A> Iterator for Box<I, A> where I: Iterator + ?Sized, A: Allocator, type Item = <I as Iterator>::Item; impl<F, A> Future for Box<F, A> where F: Future + Unpin + ?Sized, A: Allocator + 'static, type Output = <F as Future>::Output; impl<R: Read + ?Sized> Read for Box<R> impl<W: Write + ?Sized> Write for Box<W>
Converts a [T; N]
into a Box<[T]>
This conversion moves the array to newly heap-allocated memory.
Examples
let boxed: Box<[u8]> = Box::from([4, 2]); println!("{:?}", boxed);
pub fn from(s: Box<[T], A>) -> Vec<T, A>
Convert 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]);
impl From<Box<CStr, Global>> for CString
fn from(s: Box<CStr>) -> CString
impl From<Box<OsStr, Global>> for OsString
fn from(boxed: Box<OsStr>) -> OsString
impl From<Box<Path, Global>> for PathBuf
fn from(boxed: Box<Path>) -> PathBuf
Converts a Box<Path>
into a PathBuf
This conversion does not allocate or copy memory.
pub fn from(boxed: Box<T, A>) -> Pin<Box<T, A>>
impl<P> Future for Pin<P> where P: DerefMut, <P as Deref>::Target: Future, type Output = <<P as Deref>::Target as Future>::Output;
Converts a Box<T>
into a Pin<Box<T>>
This conversion does not allocate on the heap and happens in place.
pub fn from(v: Box<T, Global>) -> Rc<T>
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);
pub fn from(v: Box<T, Global>) -> Arc<T>
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[..]);
pub fn from(s: Box<str, A>) -> Box<[u8], A>
impl<I, A> Iterator for Box<I, A> where I: Iterator + ?Sized, A: Allocator, type Item = <I as Iterator>::Item; impl<F, A> Future for Box<F, A> where F: Future + Unpin + ?Sized, A: Allocator + 'static, type Output = <F as Future>::Output; impl<R: Read + ?Sized> Read for Box<R> impl<W: Write + ?Sized> Write for Box<W>
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);
impl From<Box<str, Global>> for String
pub fn from(s: Box<str, Global>) -> String
Converts the given boxed str
slice to a String
. It is notable that the str
slice is owned.
Examples
Basic usage:
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)
impl From<CString> for Box<CStr>
fn from(s: CString) -> Box<CStr>
impl<I, A> Iterator for Box<I, A> where I: Iterator + ?Sized, A: Allocator, type Item = <I as Iterator>::Item; impl<F, A> Future for Box<F, A> where F: Future + Unpin + ?Sized, A: Allocator + 'static, type Output = <F as Future>::Output; impl<R: Read + ?Sized> Read for Box<R> impl<W: Write + ?Sized> Write for Box<W>
pub fn from(cow: Cow<'_, [T]>) -> Box<[T], Global>
impl<I, A> Iterator for Box<I, A> where I: Iterator + ?Sized, A: Allocator, type Item = <I as Iterator>::Item; impl<F, A> Future for Box<F, A> where F: Future + Unpin + ?Sized, A: Allocator + 'static, type Output = <F as Future>::Output; impl<R: Read + ?Sized> Read for Box<R> impl<W: Write + ?Sized> Write for Box<W>
Performs the conversion.
impl From<Cow<'_, CStr>> for Box<CStr>
fn from(cow: Cow<'_, CStr>) -> Box<CStr>
impl<I, A> Iterator for Box<I, A> where I: Iterator + ?Sized, A: Allocator, type Item = <I as Iterator>::Item; impl<F, A> Future for Box<F, A> where F: Future + Unpin + ?Sized, A: Allocator + 'static, type Output = <F as Future>::Output; impl<R: Read + ?Sized> Read for Box<R> impl<W: Write + ?Sized> Write for Box<W>
Performs the conversion.
impl From<Cow<'_, OsStr>> for Box<OsStr>
fn from(cow: Cow<'_, OsStr>) -> Box<OsStr>
impl<I, A> Iterator for Box<I, A> where I: Iterator + ?Sized, A: Allocator, type Item = <I as Iterator>::Item; impl<F, A> Future for Box<F, A> where F: Future + Unpin + ?Sized, A: Allocator + 'static, type Output = <F as Future>::Output; impl<R: Read + ?Sized> Read for Box<R> impl<W: Write + ?Sized> Write for Box<W>
Performs the conversion.
impl From<Cow<'_, Path>> for Box<Path>
fn from(cow: Cow<'_, Path>) -> Box<Path>
impl<I, A> Iterator for Box<I, A> where I: Iterator + ?Sized, A: Allocator, type Item = <I as Iterator>::Item; impl<F, A> Future for Box<F, A> where F: Future + Unpin + ?Sized, A: Allocator + 'static, type Output = <F as Future>::Output; impl<R: Read + ?Sized> Read for Box<R> impl<W: Write + ?Sized> Write for Box<W>
Creates a boxed Path
from a clone-on-write pointer.
Converting from a Cow::Owned
does not clone or allocate.
impl<'_> From<Cow<'_, str>> for Box<str, Global>
pub fn from(cow: Cow<'_, str>) -> Box<str, Global>
impl<I, A> Iterator for Box<I, A> where I: Iterator + ?Sized, A: Allocator, type Item = <I as Iterator>::Item; impl<F, A> Future for Box<F, A> where F: Future + Unpin + ?Sized, A: Allocator + 'static, type Output = <F as Future>::Output; impl<R: Read + ?Sized> Read for Box<R> impl<W: Write + ?Sized> Write for Box<W>
Performs the conversion.
impl<'a> From<Cow<'a, str>> for Box<dyn Error>
fn from(err: Cow<'a, str>) -> Box<dyn Error>
impl<I, A> Iterator for Box<I, A> where I: Iterator + ?Sized, A: Allocator, type Item = <I as Iterator>::Item; impl<F, A> Future for Box<F, A> where F: Future + Unpin + ?Sized, A: Allocator + 'static, type Output = <F as Future>::Output; impl<R: Read + ?Sized> Read for Box<R> impl<W: Write + ?Sized> Write for Box<W>
impl<'a, 'b> From<Cow<'b, str>> for Box<dyn Error + Send + Sync + 'a>
fn from(err: Cow<'b, str>) -> Box<dyn Error + Send + Sync + 'a>
impl<I, A> Iterator for Box<I, A> where I: Iterator + ?Sized, A: Allocator, type Item = <I as Iterator>::Item; impl<F, A> Future for Box<F, A> where F: Future + Unpin + ?Sized, A: Allocator + 'static, type Output = <F as Future>::Output; impl<R: Read + ?Sized> Read for Box<R> impl<W: Write + ?Sized> Write for Box<W>
Converts a Cow
into a box of dyn Error
+ Send
+ Sync
.
Examples
use std::error::Error; use std::mem; use std::borrow::Cow; let a_cow_str_error = Cow::from("a str error"); let a_boxed_error = Box::<dyn Error + Send + Sync>::from(a_cow_str_error); assert!( mem::size_of::<Box<dyn Error + Send + Sync>>() == mem::size_of_val(&a_boxed_error))
impl<'a, E: Error + 'a> From<E> for Box<dyn Error + 'a>
fn from(err: E) -> Box<dyn Error + 'a>
impl<I, A> Iterator for Box<I, A> where I: Iterator + ?Sized, A: Allocator, type Item = <I as Iterator>::Item; impl<F, A> Future for Box<F, A> where F: Future + Unpin + ?Sized, A: Allocator + 'static, type Output = <F as Future>::Output; impl<R: Read + ?Sized> Read for Box<R> impl<W: Write + ?Sized> Write for Box<W>
Converts a type of Error
into a box of dyn Error
.
Examples
use std::error::Error; use std::fmt; use std::mem; #[derive(Debug)] struct AnError; impl fmt::Display for AnError { fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { write!(f , "An error") } } impl Error for AnError {} let an_error = AnError; assert!(0 == mem::size_of_val(&an_error)); let a_boxed_error = Box::<dyn Error>::from(an_error); assert!(mem::size_of::<Box<dyn Error>>() == mem::size_of_val(&a_boxed_error))
impl<'a, E: Error + Send + Sync + 'a> From<E> for Box<dyn Error + Send + Sync + 'a>
fn from(err: E) -> Box<dyn Error + Send + Sync + 'a>
impl<I, A> Iterator for Box<I, A> where I: Iterator + ?Sized, A: Allocator, type Item = <I as Iterator>::Item; impl<F, A> Future for Box<F, A> where F: Future + Unpin + ?Sized, A: Allocator + 'static, type Output = <F as Future>::Output; impl<R: Read + ?Sized> Read for Box<R> impl<W: Write + ?Sized> Write for Box<W>
Converts a type of Error
+ Send
+ Sync
into a box of dyn Error
+ Send
+ Sync
.
Examples
use std::error::Error; use std::fmt; use std::mem; #[derive(Debug)] struct AnError; impl fmt::Display for AnError { fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { write!(f , "An error") } } impl Error for AnError {} unsafe impl Send for AnError {} unsafe impl Sync for AnError {} let an_error = AnError; assert!(0 == mem::size_of_val(&an_error)); let a_boxed_error = Box::<dyn Error + Send + Sync>::from(an_error); assert!( mem::size_of::<Box<dyn Error + Send + Sync>>() == mem::size_of_val(&a_boxed_error))
impl From<OsString> for Box<OsStr>
fn from(s: OsString) -> Box<OsStr>
impl<I, A> Iterator for Box<I, A> where I: Iterator + ?Sized, A: Allocator, type Item = <I as Iterator>::Item; impl<F, A> Future for Box<F, A> where F: Future + Unpin + ?Sized, A: Allocator + 'static, type Output = <F as Future>::Output; impl<R: Read + ?Sized> Read for Box<R> impl<W: Write + ?Sized> Write for Box<W>
impl From<PathBuf> for Box<Path>
fn from(p: PathBuf) -> Box<Path>
impl<I, A> Iterator for Box<I, A> where I: Iterator + ?Sized, A: Allocator, type Item = <I as Iterator>::Item; impl<F, A> Future for Box<F, A> where F: Future + Unpin + ?Sized, A: Allocator + 'static, type Output = <F as Future>::Output; impl<R: Read + ?Sized> Read for Box<R> impl<W: Write + ?Sized> Write for Box<W>
Converts a PathBuf
into a Box<Path>
This conversion currently should not allocate memory, but this behavior is not guaranteed on all platforms or in all future versions.
impl From<String> for Box<str, Global>
pub fn from(s: String) -> Box<str, Global>
impl<I, A> Iterator for Box<I, A> where I: Iterator + ?Sized, A: Allocator, type Item = <I as Iterator>::Item; impl<F, A> Future for Box<F, A> where F: Future + Unpin + ?Sized, A: Allocator + 'static, type Output = <F as Future>::Output; impl<R: Read + ?Sized> Read for Box<R> impl<W: Write + ?Sized> Write for Box<W>
Converts the given String
to a boxed str
slice that is owned.
Examples
Basic usage:
let s1: String = String::from("hello world"); let s2: Box<str> = Box::from(s1); let s3: String = String::from(s2); assert_eq!("hello world", s3)
impl From<String> for Box<dyn Error + Send + Sync>
fn from(err: String) -> Box<dyn Error + Send + Sync>
impl<I, A> Iterator for Box<I, A> where I: Iterator + ?Sized, A: Allocator, type Item = <I as Iterator>::Item; impl<F, A> Future for Box<F, A> where F: Future + Unpin + ?Sized, A: Allocator + 'static, type Output = <F as Future>::Output; impl<R: Read + ?Sized> Read for Box<R> impl<W: Write + ?Sized> Write for Box<W>
Converts a String
into a box of dyn Error
+ Send
+ Sync
.
Examples
use std::error::Error; use std::mem; let a_string_error = "a string error".to_string(); let a_boxed_error = Box::<dyn Error + Send + Sync>::from(a_string_error); assert!( mem::size_of::<Box<dyn Error + Send + Sync>>() == mem::size_of_val(&a_boxed_error))
impl From<String> for Box<dyn Error>
fn from(str_err: String) -> Box<dyn Error>
impl<I, A> Iterator for Box<I, A> where I: Iterator + ?Sized, A: Allocator, type Item = <I as Iterator>::Item; impl<F, A> Future for Box<F, A> where F: Future + Unpin + ?Sized, A: Allocator + 'static, type Output = <F as Future>::Output; impl<R: Read + ?Sized> Read for Box<R> impl<W: Write + ?Sized> Write for Box<W>
impl<T> From<T> for Box<T, Global>
pub fn from(t: T) -> Box<T, Global>
impl<I, A> Iterator for Box<I, A> where I: Iterator + ?Sized, A: Allocator, type Item = <I as Iterator>::Item; impl<F, A> Future for Box<F, A> where F: Future + Unpin + ?Sized, A: Allocator + 'static, type Output = <F as Future>::Output; impl<R: Read + ?Sized> Read for Box<R> impl<W: Write + ?Sized> Write for Box<W>
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);
pub fn from(v: Vec<T, A>) -> Box<[T], A>
impl<I, A> Iterator for Box<I, A> where I: Iterator + ?Sized, A: Allocator, type Item = <I as Iterator>::Item; impl<F, A> Future for Box<F, A> where F: Future + Unpin + ?Sized, A: Allocator + 'static, type Output = <F as Future>::Output; impl<R: Read + ?Sized> Read for Box<R> impl<W: Write + ?Sized> Write for Box<W>
Convert a vector into a boxed slice.
If v
has excess capacity, its items will be moved into a newly-allocated buffer with exactly the right capacity.
Examples
assert_eq!(Box::from(vec![1, 2, 3]), vec![1, 2, 3].into_boxed_slice());
impl FromIterator<Box<str, Global>> for String
pub fn from_iter<I>(iter: I) -> String where
I: IntoIterator<Item = Box<str, Global>>,
Creates a value from an iterator. Read more
impl<I> FromIterator<I> for Box<[I], Global>
pub fn from_iter<T>(iter: T) -> Box<[I], Global> where
T: IntoIterator<Item = I>,
impl<I, A> Iterator for Box<I, A> where I: Iterator + ?Sized, A: Allocator, type Item = <I as Iterator>::Item; impl<F, A> Future for Box<F, A> where F: Future + Unpin + ?Sized, A: Allocator + 'static, type Output = <F as Future>::Output; impl<R: Read + ?Sized> Read for Box<R> impl<W: Write + ?Sized> Write for Box<W>
Creates a value from an iterator. Read more
type Output = <F as Future>::Output
The type of value produced on completion.
pub fn poll(
self: Pin<&mut Box<F, A>>,
cx: &mut Context<'_>
) -> Poll<<Box<F, A> as Future>::Output>
Attempt to resolve the future to a final value, registering the current task for wakeup if the value is not yet available. Read more
type Yield = <G as Generator<R>>::Yield
The type of value this generator yields. Read more
type Return = <G as Generator<R>>::Return
The type of value this generator returns. Read more
pub fn resume(
self: Pin<&mut Box<G, A>>,
arg: R
) -> GeneratorState<<Box<G, A> as Generator<R>>::Yield, <Box<G, A> as Generator<R>>::Return>
Resumes the execution of this generator. Read more
pub fn finish(&self) -> u64
Returns the hash value for the values written so far. Read more
pub fn write(&mut self, bytes: &[u8])
Writes some data into this Hasher
. Read more
pub fn write_u8(&mut self, i: u8)
Writes a single u8
into this hasher.
pub fn write_u16(&mut self, i: u16)
Writes a single u16
into this hasher.
pub fn write_u32(&mut self, i: u32)
Writes a single u32
into this hasher.
pub fn write_u64(&mut self, i: u64)
Writes a single u64
into this hasher.
pub fn write_u128(&mut self, i: u128)
Writes a single u128
into this hasher.
pub fn write_usize(&mut self, i: usize)
Writes a single usize
into this hasher.
pub fn write_i8(&mut self, i: i8)
Writes a single i8
into this hasher.
pub fn write_i16(&mut self, i: i16)
Writes a single i16
into this hasher.
pub fn write_i32(&mut self, i: i32)
Writes a single i32
into this hasher.
pub fn write_i64(&mut self, i: i64)
Writes a single i64
into this hasher.
pub fn write_i128(&mut self, i: i128)
Writes a single i128
into this hasher.
pub fn write_isize(&mut self, i: isize)
Writes a single isize
into this hasher.
type Item = <I as Iterator>::Item
The type of the elements being iterated over.
pub fn next(&mut self) -> Option<<I as Iterator>::Item>
Advances the iterator and returns the next value. Read more
pub fn size_hint(&self) -> (usize, Option<usize>)
Returns the bounds on the remaining length of the iterator. Read more
pub fn nth(&mut self, n: usize) -> Option<<I as Iterator>::Item>
Returns the n
th element of the iterator. Read more
pub fn last(self) -> Option<<I as Iterator>::Item>
Consumes the iterator, returning the last element. Read more
fn count(self) -> usize
Consumes the iterator, counting the number of iterations and returning it. Read more
fn advance_by(&mut self, n: usize) -> Result<(), usize>
iter_advance_by
#77404)recently added
Advances the iterator by n
elements. Read more
fn step_by(self, step: usize) -> StepBy<Self>
impl<I> Iterator for StepBy<I> where I: Iterator, type Item = <I as Iterator>::Item;
Creates an iterator starting at the same point, but stepping by the given amount at each iteration. Read more
fn chain<U>(self, other: U) -> Chain<Self, <U as IntoIterator>::IntoIter> where
U: IntoIterator<Item = Self::Item>,
impl<A, B> Iterator for Chain<A, B> where B: Iterator<Item = <A as Iterator>::Item>, A: Iterator, type Item = <A as Iterator>::Item;
Takes two iterators and creates a new iterator over both in sequence. Read more
fn zip<U>(self, other: U) -> Zip<Self, <U as IntoIterator>::IntoIter> where
U: IntoIterator,
impl<A, B> Iterator for Zip<A, B> where B: Iterator, A: Iterator, type Item = (<A as Iterator>::Item, <B as Iterator>::Item);
‘Zips up’ two iterators into a single iterator of pairs. Read more
impl<I> Iterator for Intersperse<I> where I: Iterator, <I as Iterator>::Item: Clone, type Item = <I as Iterator>::Item;
iter_intersperse
#79524)recently added
Creates a new iterator which places a copy of separator
between adjacent items of the original iterator. Read more
fn intersperse_with<G>(self, separator: G) -> IntersperseWith<Self, G> where
G: FnMut() -> Self::Item,
impl<I, G> Iterator for IntersperseWith<I, G> where I: Iterator, G: FnMut() -> <I as Iterator>::Item, type Item = <I as Iterator>::Item;
iter_intersperse
#79524)recently added
Creates a new iterator which places an item generated by separator
between adjacent items of the original iterator. Read more
impl<B, I, F> Iterator for Map<I, F> where F: FnMut(<I as Iterator>::Item) -> B, I: Iterator, type Item = B;
Takes a closure and creates an iterator which calls that closure on each element. Read more
Calls a closure on each element of an iterator. Read more
impl<I, P> Iterator for Filter<I, P> where I: Iterator, P: FnMut(&<I as Iterator>::Item) -> bool, type Item = <I as Iterator>::Item;
Creates an iterator which uses a closure to determine if an element should be yielded. Read more
impl<B, I, F> Iterator for FilterMap<I, F> where F: FnMut(<I as Iterator>::Item) -> Option<B>, I: Iterator, type Item = B;
Creates an iterator that both filters and maps. Read more
fn enumerate(self) -> Enumerate<Self>
impl<I> Iterator for Enumerate<I> where I: Iterator, type Item = (usize, <I as Iterator>::Item);
Creates an iterator which gives the current iteration count as well as the next value. Read more
fn peekable(self) -> Peekable<Self>
impl<I> Iterator for Peekable<I> where I: Iterator, type Item = <I as Iterator>::Item;
Creates an iterator which can use the peek
and peek_mut
methods to look at the next element of the iterator without consuming it. See their documentation for more information. Read more
impl<I, P> Iterator for SkipWhile<I, P> where I: Iterator, P: FnMut(&<I as Iterator>::Item) -> bool, type Item = <I as Iterator>::Item;
impl<I, P> Iterator for TakeWhile<I, P> where I: Iterator, P: FnMut(&<I as Iterator>::Item) -> bool, type Item = <I as Iterator>::Item;
Creates an iterator that yields elements based on a predicate. Read more
fn map_while<B, P>(self, predicate: P) -> MapWhile<Self, P> where
P: FnMut(Self::Item) -> Option<B>,
impl<B, I, P> Iterator for MapWhile<I, P> where I: Iterator, P: FnMut(<I as Iterator>::Item) -> Option<B>, type Item = B;
iter_map_while
#68537)recently added
Creates an iterator that both yields elements based on a predicate and maps. Read more
fn skip(self, n: usize) -> Skip<Self>
impl<I> Iterator for Skip<I> where I: Iterator, type Item = <I as Iterator>::Item;
Creates an iterator that skips the first n
elements. Read more
fn take(self, n: usize) -> Take<Self>
impl<I> Iterator for Take<I> where I: Iterator, type Item = <I as Iterator>::Item;
Creates an iterator that yields the first n
elements, or fewer if the underlying iterator ends sooner. Read more
fn scan<St, B, F>(self, initial_state: St, f: F) -> Scan<Self, St, F> where
F: FnMut(&mut St, Self::Item) -> Option<B>,
impl<B, I, St, F> Iterator for Scan<I, St, F> where F: FnMut(&mut St, <I as Iterator>::Item) -> Option<B>, I: Iterator, type Item = B;
An iterator adapter similar to fold
that holds internal state and produces a new iterator. Read more
fn flat_map<U, F>(self, f: F) -> FlatMap<Self, U, F> where
F: FnMut(Self::Item) -> U,
U: IntoIterator,
impl<I, U, F> Iterator for FlatMap<I, U, F> where F: FnMut(<I as Iterator>::Item) -> U, I: Iterator, U: IntoIterator, type Item = <U as IntoIterator>::Item;
Creates an iterator that works like map, but flattens nested structure. Read more
fn flatten(self) -> Flatten<Self> where
Self::Item: IntoIterator,
impl<I, U> Iterator for Flatten<I> where I: Iterator, U: Iterator, <I as Iterator>::Item: IntoIterator, <<I as Iterator>::Item as IntoIterator>::IntoIter == U, <<I as Iterator>::Item as IntoIterator>::Item == <U as Iterator>::Item, type Item = <U as Iterator>::Item;
Creates an iterator that flattens nested structure. Read more
fn fuse(self) -> Fuse<Self>
impl<I> Iterator for Fuse<I> where I: Iterator, type Item = <I as Iterator>::Item;
impl<I, F> Iterator for Inspect<I, F> where F: FnMut(&<I as Iterator>::Item), I: Iterator, type Item = <I as Iterator>::Item;
Does something with each element of an iterator, passing the value on. Read more
fn by_ref(&mut self) -> &mut Self
Borrows an iterator, rather than consuming it. Read more
fn collect<B>(self) -> B where
B: FromIterator<Self::Item>,
Transforms an iterator into a collection. Read more
Consumes an iterator, creating two collections from it. Read more
iter_partition_in_place
#62543)new API
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
iter_is_partitioned
#62544)new API
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
An iterator method that applies a function as long as it returns successfully, producing a single, final value. Read more
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
Folds every element into an accumulator by applying an operation, returning the final result. Read more
Reduces the elements to a single one, by repeatedly applying a reducing operation. Read more
Tests if every element of the iterator matches a predicate. Read more
Tests if any element of the iterator matches a predicate. Read more
Searches for an element of an iterator that satisfies a predicate. Read more
Applies function to the elements of iterator and returns the first non-none result. Read more
try_find
#63178)new API
Applies function to the elements of iterator and returns the first true result or the first error. Read more
Searches for an element in an iterator, returning its index. Read more
fn rposition<P>(&mut self, predicate: P) -> Option<usize> where
Self: ExactSizeIterator + DoubleEndedIterator,
P: FnMut(Self::Item) -> bool,
Searches for an element in an iterator from the right, returning its index. Read more
Returns the maximum element of an iterator. Read more
Returns the minimum element of an iterator. Read more
Returns the element that gives the maximum value from the specified function. Read more
Returns the element that gives the maximum value with respect to the specified comparison function. Read more
Returns the element that gives the minimum value from the specified function. Read more
Returns the element that gives the minimum value with respect to the specified comparison function. Read more
fn rev(self) -> Rev<Self> where
Self: DoubleEndedIterator,
impl<I> Iterator for Rev<I> where I: DoubleEndedIterator, type Item = <I as Iterator>::Item;
Reverses an iterator’s direction. Read more
Converts an iterator of pairs into a pair of containers. Read more
fn copied<'a, T>(self) -> Copied<Self> where
Self: Iterator<Item = &'a T>,
T: 'a + Copy,
impl<'a, I, T> Iterator for Copied<I> where T: 'a + Copy, I: Iterator<Item = &'a T>, type Item = T;
Creates an iterator which copies all of its elements. Read more
impl<'a, I, T> Iterator for Cloned<I> where T: 'a + Clone, I: Iterator<Item = &'a T>, type Item = T;
impl<I> Iterator for Cycle<I> where I: Clone + Iterator, type Item = <I as Iterator>::Item;
Repeats an iterator endlessly. Read more
Sums the elements of an iterator. Read more
Iterates over the entire iterator, multiplying all the elements Read more
fn cmp<I>(self, other: I) -> Ordering where
I: IntoIterator<Item = Self::Item>,
Self::Item: Ord,
Lexicographically compares the elements of this Iterator
with those of another. Read more
fn cmp_by<I, F>(self, other: I, cmp: F) -> Ordering where
F: FnMut(Self::Item, <I as IntoIterator>::Item) -> Ordering,
I: IntoIterator,
Lexicographically compares the elements of this Iterator
with those of another with respect to the specified comparison function. Read more
fn partial_cmp<I>(self, other: I) -> Option<Ordering> where
I: IntoIterator,
Self::Item: PartialOrd<<I as IntoIterator>::Item>,
Lexicographically compares the elements of this Iterator
with those of another. Read more
fn partial_cmp_by<I, F>(self, other: I, partial_cmp: F) -> Option<Ordering> where
F: FnMut(Self::Item, <I as IntoIterator>::Item) -> Option<Ordering>,
I: IntoIterator,
Lexicographically compares the elements of this Iterator
with those of another with respect to the specified comparison function. Read more
fn eq<I>(self, other: I) -> bool where
I: IntoIterator,
Self::Item: PartialEq<<I as IntoIterator>::Item>,
fn eq_by<I, F>(self, other: I, eq: F) -> bool where
F: FnMut(Self::Item, <I as IntoIterator>::Item) -> bool,
I: IntoIterator,
Determines if the elements of this Iterator
are equal to those of another with respect to the specified equality function. Read more
fn ne<I>(self, other: I) -> bool where
I: IntoIterator,
Self::Item: PartialEq<<I as IntoIterator>::Item>,
fn lt<I>(self, other: I) -> bool where
I: IntoIterator,
Self::Item: PartialOrd<<I as IntoIterator>::Item>,
Determines if the elements of this Iterator
are lexicographically less than those of another. Read more
fn le<I>(self, other: I) -> bool where
I: IntoIterator,
Self::Item: PartialOrd<<I as IntoIterator>::Item>,
Determines if the elements of this Iterator
are lexicographically less or equal to those of another. Read more
fn gt<I>(self, other: I) -> bool where
I: IntoIterator,
Self::Item: PartialOrd<<I as IntoIterator>::Item>,
Determines if the elements of this Iterator
are lexicographically greater than those of another. Read more
fn ge<I>(self, other: I) -> bool where
I: IntoIterator,
Self::Item: PartialOrd<<I as IntoIterator>::Item>,
Determines if the elements of this Iterator
are lexicographically greater than or equal to those of another. Read more
fn is_sorted(self) -> bool where
Self::Item: PartialOrd<Self::Item>,
is_sorted
#53485)new API
Checks if the elements of this iterator are sorted. Read more
is_sorted
#53485)new API
Checks if the elements of this iterator are sorted using the given comparator function. Read more
fn is_sorted_by_key<F, K>(self, f: F) -> bool where
F: FnMut(Self::Item) -> K,
K: PartialOrd<K>,
is_sorted
#53485)new API
Checks if the elements of this iterator are sorted using the given key extraction function. Read more
pub fn cmp(&self, other: &Box<T, A>) -> Ordering
fn max(self, other: Self) -> Self
Compares and returns the maximum of two values. Read more
fn min(self, other: Self) -> Self
Compares and returns the minimum of two values. Read more
fn clamp(self, min: Self, max: Self) -> Self
Restrict a value to a certain interval. Read more
pub fn eq(&self, other: &Box<T, A>) -> bool
This method tests for self
and other
values to be equal, and is used by ==
. Read more
pub fn ne(&self, other: &Box<T, A>) -> bool
This method tests for !=
.
impl<T, A> PartialOrd<Box<T, A>> for Box<T, A> where
T: PartialOrd<T> + ?Sized,
A: Allocator,
pub fn partial_cmp(&self, other: &Box<T, A>) -> Option<Ordering>
This method returns an ordering between self
and other
values if one exists. Read more
pub fn lt(&self, other: &Box<T, A>) -> bool
This method tests less than (for self
and other
) and is used by the <
operator. Read more
pub fn le(&self, other: &Box<T, A>) -> bool
This method tests less than or equal to (for self
and other
) and is used by the <=
operator. Read more
pub fn ge(&self, other: &Box<T, A>) -> bool
This method tests greater than or equal to (for self
and other
) and is used by the >=
operator. Read more
pub fn gt(&self, other: &Box<T, A>) -> bool
This method tests greater than (for self
and other
) and is used by the >
operator. Read more
pub fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>
Formats the value using the given formatter.
impl<R: Read + ?Sized> Read for Box<R>
fn read(&mut self, buf: &mut [u8]) -> Result<usize>
Pull some bytes from this source into the specified buffer, returning how many bytes were read. Read more
fn read_vectored(&mut self, bufs: &mut [IoSliceMut<'_>]) -> Result<usize>
Like read
, except that it reads into a slice of buffers. Read more
fn is_read_vectored(&self) -> bool
Determines if this Read
er has an efficient read_vectored
implementation. Read more
unsafe fn initializer(&self) -> Initializer
Determines if this Read
er can work with buffers of uninitialized memory. Read more
fn read_to_end(&mut self, buf: &mut Vec<u8>) -> Result<usize>
Read all bytes until EOF in this source, placing them into buf
. Read more
fn read_to_string(&mut self, buf: &mut String) -> Result<usize>
Read all bytes until EOF in this source, appending them to buf
. Read more
fn read_exact(&mut self, buf: &mut [u8]) -> Result<()>
Read the exact number of bytes required to fill buf
. Read more
Creates a “by reference” adapter for this instance of Read
. Read more
impl<R: Read> Iterator for Bytes<R> type Item = Result<u8>;
impl<T: Read, U: Read> Read for Chain<T, U>
Creates an adapter which will chain this stream with another. Read more
impl<T: Read> Read for Take<T>
Creates an adapter which will read at most limit
bytes from it. Read more
impl<S: Seek + ?Sized> Seek for Box<S>
fn seek(&mut self, pos: SeekFrom) -> Result<u64>
Seek to an offset, in bytes, in a stream. Read more
fn stream_position(&mut self) -> Result<u64>
Returns the current seek position from the start of the stream. Read more
fn rewind(&mut self) -> Result<()>
Rewind to the beginning of a stream. Read more
fn stream_len(&mut self) -> Result<u64>
Returns the length of this stream (in bytes). Read more
type Item = <S as Stream>::Item
The type of items yielded by the stream.
pub fn poll_next(
self: Pin<&mut Box<S, Global>>,
cx: &mut Context<'_>
) -> Poll<Option<<Box<S, Global> as Stream>::Item>>
Attempt to pull out the next value of this stream, registering the current task for wakeup if the value is not yet available, and returning None
if the stream is exhausted. Read more
pub fn size_hint(&self) -> (usize, Option<usize>)
Returns the bounds on the remaining length of the stream. Read more
impl<T, const N: usize> TryFrom<Box<[T], Global>> for Box<[T; N], Global>
type Error = Box<[T], Global>
The type returned in the event of a conversion error.
pub fn try_from(
boxed_slice: Box<[T], Global>
) -> Result<Box<[T; N], Global>, <Box<[T; N], Global> as TryFrom<Box<[T], Global>>>::Error>
Performs the conversion.
impl<W: Write + ?Sized> Write for Box<W>
fn write(&mut self, buf: &[u8]) -> Result<usize>
Write a buffer into this writer, returning how many bytes were written. Read more
fn write_vectored(&mut self, bufs: &[IoSlice<'_>]) -> Result<usize>
fn is_write_vectored(&self) -> bool
Determines if this Write
r has an efficient write_vectored
implementation. Read more
fn flush(&mut self) -> Result<()>
Flush this output stream, ensuring that all intermediately buffered contents reach their destination. Read more
fn write_all(&mut self, buf: &[u8]) -> Result<()>
Attempts to write an entire buffer into this writer. Read more
fn write_fmt(&mut self, fmt: Arguments<'_>) -> Result<()>
Writes a formatted string into this writer, returning any error encountered. Read more
fn write_all_vectored(&mut self, bufs: &mut [IoSlice<'_>]) -> Result<()>
Attempts to write multiple buffers into this writer. Read more
Creates a “by reference” adapter for this instance of Write
. Read more
impl<T, U, A> CoerceUnsized<Box<U, A>> for Box<T, A> where
T: Unsize<U> + ?Sized,
U: ?Sized,
A: Allocator,
impl<T, U> DispatchFromDyn<Box<U, Global>> for Box<T, Global> where
T: Unsize<U> + ?Sized,
U: ?Sized,
impl<I, A> FusedIterator for Box<I, A> where
I: FusedIterator + ?Sized,
A: Allocator,
Auto Trait Implementations
impl<T: ?Sized, A> RefUnwindSafe for Box<T, A> where
A: RefUnwindSafe,
T: RefUnwindSafe,
impl<T: ?Sized, A> UnwindSafe for Box<T, A> where
A: UnwindSafe,
T: UnwindSafe,
Blanket Implementations
impl<T> From<!> for T
pub fn from(t: !) -> T
Performs the conversion.
impl<T> From<T> for T
pub fn from(t: T) -> T
Performs the conversion.
pub fn into(self) -> U
Performs the conversion.
type Output = <F as Future>::Output
The output that the future will produce on completion.
type Future = F
Which kind of future are we turning this into?
pub fn into_future(self) -> <F as IntoFuture>::Future
Creates a future from a value.
type Item = <I as Iterator>::Item
The type of the elements being iterated over.
type IntoIter = I
Which kind of iterator are we turning this into?
pub fn into_iter(self) -> I
Creates an iterator from a value. Read more
type Searcher = CharPredicateSearcher<'a, F>
pattern
#27721)API not fully fleshed out and ready to be stabilized
Associated searcher for this pattern
pub fn into_searcher(self, haystack: &'a str) -> CharPredicateSearcher<'a, F>
pattern
#27721)API not fully fleshed out and ready to be stabilized
Constructs the associated searcher from self
and the haystack
to search in. Read more
pub fn is_contained_in(self, haystack: &'a str) -> bool
pattern
#27721)API not fully fleshed out and ready to be stabilized
Checks whether the pattern matches anywhere in the haystack
pub fn is_prefix_of(self, haystack: &'a str) -> bool
pattern
#27721)API not fully fleshed out and ready to be stabilized
Checks whether the pattern matches at the front of the haystack
pub fn strip_prefix_of(self, haystack: &'a str) -> Option<&'a str>
pattern
#27721)API not fully fleshed out and ready to be stabilized
Removes the pattern from the front of haystack, if it matches.
pub fn is_suffix_of(self, haystack: &'a str) -> bool where
CharPredicateSearcher<'a, F>: ReverseSearcher<'a>,
pattern
#27721)API not fully fleshed out and ready to be stabilized
Checks whether the pattern matches at the back of the haystack
pub fn strip_suffix_of(self, haystack: &'a str) -> Option<&'a str> where
CharPredicateSearcher<'a, F>: ReverseSearcher<'a>,
pattern
#27721)API not fully fleshed out and ready to be stabilized
Removes the pattern from the back of haystack, if it matches.
type Owned = T
The resulting type after obtaining ownership.
pub fn to_owned(&self) -> T
Creates owned data from borrowed data, usually by cloning. Read more
pub fn clone_into(&self, target: &mut T)
toowned_clone_into
#41263)recently added
Uses borrowed data to replace owned data, usually by cloning. Read more
type Error = Infallible
The type returned in the event of a conversion error.
pub fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>
Performs the conversion.
type Error = <U as TryFrom<T>>::Error
The type returned in the event of a conversion error.
pub fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>
Performs the conversion.
© 2010 The Rust Project Developers
Licensed under the Apache License, Version 2.0 or the MIT license, at your option.
https://doc.rust-lang.org/std/boxed/struct.Box.html