Struct std::rc::Rc
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pub struct Rc<T> where T: ?Sized {
// some fields omitted
}A reference-counted pointer type over an immutable value.
See the module level documentation for more details.
Methods
impl<T> Rc<T>
fn new(value: T) -> Rc<T>
Constructs a new Rc<T>.
Examples
fn main() { use std::rc::Rc; let five = Rc::new(5); }use std::rc::Rc; let five = Rc::new(5);
fn try_unwrap(rc: Rc<T>) -> Result<T, Rc<T>>
Unstable (
rc_unique #27718)Unwraps the contained value if the Rc<T> is unique.
If the Rc<T> is not unique, an Err is returned with the same
Rc<T>.
Examples
#![feature(rc_unique)] fn main() { use std::rc::Rc; let x = Rc::new(3); assert_eq!(Rc::try_unwrap(x), Ok(3)); let x = Rc::new(4); let _y = x.clone(); assert_eq!(Rc::try_unwrap(x), Err(Rc::new(4))); }#![feature(rc_unique)] use std::rc::Rc; let x = Rc::new(3); assert_eq!(Rc::try_unwrap(x), Ok(3)); let x = Rc::new(4); let _y = x.clone(); assert_eq!(Rc::try_unwrap(x), Err(Rc::new(4)));
impl<T> Rc<T> where T: ?Sized
fn downgrade(&self) -> Weak<T>
Downgrades the Rc<T> to a Weak<T> reference.
Examples
#![feature(rc_weak)] fn main() { use std::rc::Rc; let five = Rc::new(5); let weak_five = five.downgrade(); }#![feature(rc_weak)] use std::rc::Rc; let five = Rc::new(5); let weak_five = five.downgrade();
fn weak_count(this: &Rc<T>) -> usize
Unstable (
rc_counts #27718)Get the number of weak references to this value.
fn strong_count(this: &Rc<T>) -> usize
Unstable (
rc_counts #27718)Get the number of strong references to this value.
fn is_unique(rc: &Rc<T>) -> bool
Unstable (
rc_unique #27718)Returns true if there are no other Rc or Weak<T> values that share
the same inner value.
Examples
#![feature(rc_unique)] fn main() { use std::rc::Rc; let five = Rc::new(5); assert!(Rc::is_unique(&five)); }#![feature(rc_unique)] use std::rc::Rc; let five = Rc::new(5); assert!(Rc::is_unique(&five));
fn get_mut(rc: &mut Rc<T>) -> Option<&mut T>
Unstable (
rc_unique #27718)Returns a mutable reference to the contained value if the Rc<T> is
unique.
Returns None if the Rc<T> is not unique.
Examples
#![feature(rc_unique)] fn main() { use std::rc::Rc; let mut x = Rc::new(3); *Rc::get_mut(&mut x).unwrap() = 4; assert_eq!(*x, 4); let _y = x.clone(); assert!(Rc::get_mut(&mut x).is_none()); }#![feature(rc_unique)] use std::rc::Rc; let mut x = Rc::new(3); *Rc::get_mut(&mut x).unwrap() = 4; assert_eq!(*x, 4); let _y = x.clone(); assert!(Rc::get_mut(&mut x).is_none());
impl<T> Rc<T> where T: Clone
fn make_unique(&mut self) -> &mut T
Unstable (
rc_unique #27718)Make a mutable reference from the given Rc<T>.
This is also referred to as a copy-on-write operation because the inner data is cloned if the reference count is greater than one.
Examples
#![feature(rc_unique)] fn main() { use std::rc::Rc; let mut five = Rc::new(5); let mut_five = five.make_unique(); }#![feature(rc_unique)] use std::rc::Rc; let mut five = Rc::new(5); let mut_five = five.make_unique();