1.0.0[−][src]Struct alloc::rc::Rc
A single-threaded reference-counting pointer. 'Rc' stands for 'Reference Counted'.
See the module-level documentation for more details.
The inherent methods of Rc
are all associated functions, which means
that you have to call them as e.g., Rc::get_mut(&mut value)
instead of
value.get_mut()
. This avoids conflicts with methods of the inner
type T
.
Methods
impl<T> Rc<T>
[src]
pub fn new(value: T) -> Rc<T>
[src]
pub fn pin(value: T) -> Pin<Rc<T>>
1.33.0[src]
Constructs a new Pin<Rc<T>>
. If T
does not implement Unpin
, then
value
will be pinned in memory and unable to be moved.
pub fn try_unwrap(this: Self) -> Result<T, Self>
1.4.0[src]
Returns the contained value, if the Rc
has exactly one strong reference.
Otherwise, an Err
is returned with the same Rc
that was
passed in.
This will succeed even if there are outstanding weak references.
Examples
use std::rc::Rc; let x = Rc::new(3); assert_eq!(Rc::try_unwrap(x), Ok(3)); let x = Rc::new(4); let _y = Rc::clone(&x); assert_eq!(*Rc::try_unwrap(x).unwrap_err(), 4);
impl<T: ?Sized> Rc<T>
[src]
pub fn into_raw(this: Self) -> *const T
1.17.0[src]
Consumes the Rc
, returning the wrapped pointer.
To avoid a memory leak the pointer must be converted back to an Rc
using
Rc::from_raw
.
Examples
use std::rc::Rc; let x = Rc::new(10); let x_ptr = Rc::into_raw(x); assert_eq!(unsafe { *x_ptr }, 10);
pub unsafe fn from_raw(ptr: *const T) -> Self
1.17.0[src]
Constructs an Rc
from a raw pointer.
The raw pointer must have been previously returned by a call to a
Rc::into_raw
.
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
use std::rc::Rc; let x = Rc::new(10); let x_ptr = Rc::into_raw(x); unsafe { // Convert back to an `Rc` to prevent leak. let x = Rc::from_raw(x_ptr); assert_eq!(*x, 10); // Further calls to `Rc::from_raw(x_ptr)` would be memory unsafe. } // The memory was freed when `x` went out of scope above, so `x_ptr` is now dangling!
pub fn into_raw_non_null(this: Self) -> NonNull<T>
[src]
Consumes the Rc
, returning the wrapped pointer as NonNull<T>
.
Examples
#![feature(rc_into_raw_non_null)] use std::rc::Rc; let x = Rc::new(10); let ptr = Rc::into_raw_non_null(x); let deref = unsafe { *ptr.as_ref() }; assert_eq!(deref, 10);
pub fn downgrade(this: &Self) -> Weak<T>
1.4.0[src]
Creates a new Weak
pointer to this value.
Examples
use std::rc::Rc; let five = Rc::new(5); let weak_five = Rc::downgrade(&five);
pub fn weak_count(this: &Self) -> usize
1.15.0[src]
Gets the number of Weak
pointers to this value.
Examples
use std::rc::Rc; let five = Rc::new(5); let _weak_five = Rc::downgrade(&five); assert_eq!(1, Rc::weak_count(&five));
pub fn strong_count(this: &Self) -> usize
1.15.0[src]
Gets the number of strong (Rc
) pointers to this value.
Examples
use std::rc::Rc; let five = Rc::new(5); let _also_five = Rc::clone(&five); assert_eq!(2, Rc::strong_count(&five));
pub fn get_mut(this: &mut Self) -> Option<&mut T>
1.4.0[src]
Returns a mutable reference to the inner value, if there are
no other Rc
or Weak
pointers to the same value.
Returns None
otherwise, because it is not safe to
mutate a shared value.
See also make_mut
, which will clone
the inner value when it's shared.
Examples
use std::rc::Rc; let mut x = Rc::new(3); *Rc::get_mut(&mut x).unwrap() = 4; assert_eq!(*x, 4); let _y = Rc::clone(&x); assert!(Rc::get_mut(&mut x).is_none());
pub fn ptr_eq(this: &Self, other: &Self) -> bool
1.17.0[src]
Returns true
if the two Rc
s point to the same value (not
just values that compare as equal).
Examples
use std::rc::Rc; let five = Rc::new(5); let same_five = Rc::clone(&five); let other_five = Rc::new(5); assert!(Rc::ptr_eq(&five, &same_five)); assert!(!Rc::ptr_eq(&five, &other_five));
impl<T: Clone> Rc<T>
[src]
pub fn make_mut(this: &mut Self) -> &mut T
1.4.0[src]
Makes a mutable reference into the given Rc
.
If there are other Rc
or Weak
pointers to the same value,
then make_mut
will invoke clone
on the inner value to
ensure unique ownership. This is also referred to as clone-on-write.
See also get_mut
, which will fail rather than cloning.
Examples
use std::rc::Rc; let mut data = Rc::new(5); *Rc::make_mut(&mut data) += 1; // Won't clone anything let mut other_data = Rc::clone(&data); // Won't clone inner data *Rc::make_mut(&mut data) += 1; // Clones inner data *Rc::make_mut(&mut data) += 1; // Won't clone anything *Rc::make_mut(&mut other_data) *= 2; // Won't clone anything // Now `data` and `other_data` point to different values. assert_eq!(*data, 8); assert_eq!(*other_data, 12);
impl Rc<dyn Any>
[src]
pub fn downcast<T: Any>(self) -> Result<Rc<T>, Rc<dyn Any>>
1.29.0[src]
Attempt to downcast the Rc<dyn Any>
to a concrete type.
Examples
use std::any::Any; use std::rc::Rc; fn print_if_string(value: Rc<dyn Any>) { if let Ok(string) = value.downcast::<String>() { println!("String ({}): {}", string.len(), string); } } fn main() { let my_string = "Hello World".to_string(); print_if_string(Rc::new(my_string)); print_if_string(Rc::new(0i8)); }
Trait Implementations
impl<T: ?Sized> Deref for Rc<T>
[src]
impl<T: ?Sized + Unsize<U>, U: ?Sized> DispatchFromDyn<Rc<U>> for Rc<T>
[src]
impl<T: ?Sized + PartialEq> PartialEq<Rc<T>> for Rc<T>
[src]
fn eq(&self, other: &Rc<T>) -> bool
[src]
Equality for two Rc
s.
Two Rc
s are equal if their inner values are equal.
If T
also implements Eq
, two Rc
s that point to the same value are
always equal.
Examples
use std::rc::Rc; let five = Rc::new(5); assert!(five == Rc::new(5));
fn ne(&self, other: &Rc<T>) -> bool
[src]
Inequality for two Rc
s.
Two Rc
s are unequal if their inner values are unequal.
If T
also implements Eq
, two Rc
s that point to the same value are
never unequal.
Examples
use std::rc::Rc; let five = Rc::new(5); assert!(five != Rc::new(6));
impl<T: ?Sized + Eq> Eq for Rc<T>
[src]
impl<T: ?Sized + Ord> Ord for Rc<T>
[src]
fn cmp(&self, other: &Rc<T>) -> Ordering
[src]
Comparison for two Rc
s.
The two are compared by calling cmp()
on their inner values.
Examples
use std::rc::Rc; use std::cmp::Ordering; let five = Rc::new(5); assert_eq!(Ordering::Less, five.cmp(&Rc::new(6)));
fn max(self, other: Self) -> Self
1.21.0[src]
Compares and returns the maximum of two values. Read more
fn min(self, other: Self) -> Self
1.21.0[src]
Compares and returns the minimum of two values. Read more
fn clamp(self, min: Self, max: Self) -> Self
[src]
Restrict a value to a certain interval. Read more
impl<T: ?Sized + PartialOrd> PartialOrd<Rc<T>> for Rc<T>
[src]
fn partial_cmp(&self, other: &Rc<T>) -> Option<Ordering>
[src]
Partial comparison for two Rc
s.
The two are compared by calling partial_cmp()
on their inner values.
Examples
use std::rc::Rc; use std::cmp::Ordering; let five = Rc::new(5); assert_eq!(Some(Ordering::Less), five.partial_cmp(&Rc::new(6)));
fn lt(&self, other: &Rc<T>) -> bool
[src]
Less-than comparison for two Rc
s.
The two are compared by calling <
on their inner values.
Examples
use std::rc::Rc; let five = Rc::new(5); assert!(five < Rc::new(6));
fn le(&self, other: &Rc<T>) -> bool
[src]
'Less than or equal to' comparison for two Rc
s.
The two are compared by calling <=
on their inner values.
Examples
use std::rc::Rc; let five = Rc::new(5); assert!(five <= Rc::new(5));
fn gt(&self, other: &Rc<T>) -> bool
[src]
Greater-than comparison for two Rc
s.
The two are compared by calling >
on their inner values.
Examples
use std::rc::Rc; let five = Rc::new(5); assert!(five > Rc::new(4));
fn ge(&self, other: &Rc<T>) -> bool
[src]
'Greater than or equal to' comparison for two Rc
s.
The two are compared by calling >=
on their inner values.
Examples
use std::rc::Rc; let five = Rc::new(5); assert!(five >= Rc::new(5));
impl<T: ?Sized + Hash> Hash for Rc<T>
[src]
fn hash<H: Hasher>(&self, state: &mut H)
[src]
fn hash_slice<H>(data: &[Self], state: &mut H) where
H: Hasher,
1.3.0[src]
H: Hasher,
Feeds a slice of this type into the given [Hasher
]. Read more
impl<T: ?Sized> !Send for Rc<T>
[src]
impl<T: ?Sized> !Sync for Rc<T>
[src]
impl<T: ?Sized> Unpin for Rc<T>
1.33.0[src]
impl<T: ?Sized + Display> Display for Rc<T>
[src]
impl<T: ?Sized + Debug> Debug for Rc<T>
[src]
impl<T: ?Sized> Receiver for Rc<T>
[src]
impl<T: ?Sized> Drop for Rc<T>
[src]
fn drop(&mut self)
[src]
Drops the Rc
.
This will decrement the strong reference count. If the strong reference
count reaches zero then the only other references (if any) are
Weak
, so we drop
the inner value.
Examples
use std::rc::Rc; struct Foo; impl Drop for Foo { fn drop(&mut self) { println!("dropped!"); } } let foo = Rc::new(Foo); let foo2 = Rc::clone(&foo); drop(foo); // Doesn't print anything drop(foo2); // Prints "dropped!"
impl<T: ?Sized + Unsize<U>, U: ?Sized> CoerceUnsized<Rc<U>> for Rc<T>
[src]
impl<T: ?Sized> AsRef<T> for Rc<T>
1.5.0[src]
impl<T> From<T> for Rc<T>
1.6.0[src]
impl<'_, T: Clone> From<&'_ [T]> for Rc<[T]>
1.21.0[src]
impl<'_> From<&'_ str> for Rc<str>
1.21.0[src]
impl From<String> for Rc<str>
1.21.0[src]
impl<T: ?Sized> From<Box<T>> for Rc<T>
1.21.0[src]
impl<T> From<Vec<T>> for Rc<[T]>
1.21.0[src]
impl<T: ?Sized> Pointer for Rc<T>
[src]
impl<T: ?Sized> Clone for Rc<T>
[src]
fn clone(&self) -> Rc<T>
[src]
Makes a clone of the Rc
pointer.
This creates another pointer to the same inner value, increasing the strong reference count.
Examples
use std::rc::Rc; let five = Rc::new(5); let _ = Rc::clone(&five);
fn clone_from(&mut self, source: &Self)
[src]
Performs copy-assignment from source
. Read more
impl<T: Default> Default for Rc<T>
[src]
fn default() -> Rc<T>
[src]
Creates a new Rc<T>
, with the Default
value for T
.
Examples
use std::rc::Rc; let x: Rc<i32> = Default::default(); assert_eq!(*x, 0);
impl<T: ?Sized> Borrow<T> for Rc<T>
[src]
Blanket Implementations
impl<T> ToOwned for T where
T: Clone,
[src]
T: Clone,
type Owned = T
The resulting type after obtaining ownership.
fn to_owned(&Self) -> T
[src]
fn clone_into(&Self, &mut T)
[src]
impl<T> ToString for T where
T: Display + ?Sized,
[src]
T: Display + ?Sized,
impl<T, U> TryFrom<U> for T where
U: Into<T>,
[src]
U: Into<T>,
type Error = Infallible
The type returned in the event of a conversion error.
fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>
[src]
impl<T, U> Into<U> for T where
U: From<T>,
[src]
U: From<T>,
impl<T> From<T> for T
[src]
impl<T, U> TryInto<U> for T where
U: TryFrom<T>,
[src]
U: TryFrom<T>,
type Error = <U as TryFrom<T>>::Error
The type returned in the event of a conversion error.
fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>
[src]
impl<T> Borrow<T> for T where
T: ?Sized,
[src]
T: ?Sized,
impl<T> BorrowMut<T> for T where
T: ?Sized,
[src]
T: ?Sized,
fn borrow_mut(&mut self) -> &mut T
[src]
impl<T> Any for T where
T: 'static + ?Sized,
[src]
T: 'static + ?Sized,