1.0.0[−][src]Struct std::cell::Cell
A mutable memory location.
Examples
In this example, you can see that Cell<T>
enables mutation inside an
immutable struct. In other words, it enables "interior mutability".
use std::cell::Cell; struct SomeStruct { regular_field: u8, special_field: Cell<u8>, } let my_struct = SomeStruct { regular_field: 0, special_field: Cell::new(1), }; let new_value = 100; // ERROR: `my_struct` is immutable // my_struct.regular_field = new_value; // WORKS: although `my_struct` is immutable, `special_field` is a `Cell`, // which can always be mutated my_struct.special_field.set(new_value); assert_eq!(my_struct.special_field.get(), new_value);Run
See the module-level documentation for more.
Methods
impl<T> Cell<T> where
T: Copy,
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T: Copy,
pub fn get(&self) -> T
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Returns a copy of the contained value.
Examples
use std::cell::Cell; let c = Cell::new(5); let five = c.get();Run
pub fn update<F>(&self, f: F) -> T where
F: FnOnce(T) -> T,
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F: FnOnce(T) -> T,
impl<T> Cell<T>
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pub const fn new(value: T) -> Cell<T>
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Creates a new Cell
containing the given value.
Examples
use std::cell::Cell; let c = Cell::new(5);Run
pub fn set(&self, val: T)
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pub fn swap(&self, other: &Cell<T>)
1.17.0[src]
Swaps the values of two Cells.
Difference with std::mem::swap
is that this function doesn't require &mut
reference.
Examples
use std::cell::Cell; let c1 = Cell::new(5i32); let c2 = Cell::new(10i32); c1.swap(&c2); assert_eq!(10, c1.get()); assert_eq!(5, c2.get());Run
pub fn replace(&self, val: T) -> T
1.17.0[src]
Replaces the contained value, and returns it.
Examples
use std::cell::Cell; let cell = Cell::new(5); assert_eq!(cell.get(), 5); assert_eq!(cell.replace(10), 5); assert_eq!(cell.get(), 10);Run
pub fn into_inner(self) -> T
1.17.0[src]
impl<T> Cell<T> where
T: ?Sized,
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T: ?Sized,
pub const fn as_ptr(&self) -> *mut T
1.12.0[src]
Returns a raw pointer to the underlying data in this cell.
Examples
use std::cell::Cell; let c = Cell::new(5); let ptr = c.as_ptr();Run
ⓘImportant traits for &'_ mut Fpub fn get_mut(&mut self) -> &mut T
1.11.0[src]
Returns a mutable reference to the underlying data.
This call borrows Cell
mutably (at compile-time) which guarantees
that we possess the only reference.
Examples
use std::cell::Cell; let mut c = Cell::new(5); *c.get_mut() += 1; assert_eq!(c.get(), 6);Run
pub fn from_mut(t: &mut T) -> &Cell<T>
1.37.0[src]
impl<T> Cell<T> where
T: Default,
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T: Default,
impl<T> Cell<[T]>
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pub fn as_slice_of_cells(&self) -> &[Cell<T>]
1.37.0[src]
Trait Implementations
impl<T> Debug for Cell<T> where
T: Copy + Debug,
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T: Copy + Debug,
impl<T> !Sync for Cell<T> where
T: ?Sized,
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T: ?Sized,
impl<T> Eq for Cell<T> where
T: Copy + Eq,
1.2.0[src]
T: Copy + Eq,
impl<T> From<T> for Cell<T>
1.12.0[src]
impl<T> Clone for Cell<T> where
T: Copy,
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T: Copy,
impl<T> PartialEq<Cell<T>> for Cell<T> where
T: Copy + PartialEq<T>,
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T: Copy + PartialEq<T>,
impl<T> PartialOrd<Cell<T>> for Cell<T> where
T: Copy + PartialOrd<T>,
1.10.0[src]
T: Copy + PartialOrd<T>,
fn partial_cmp(&self, other: &Cell<T>) -> Option<Ordering>
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fn lt(&self, other: &Cell<T>) -> bool
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fn le(&self, other: &Cell<T>) -> bool
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fn gt(&self, other: &Cell<T>) -> bool
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fn ge(&self, other: &Cell<T>) -> bool
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impl<T> Default for Cell<T> where
T: Default,
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T: Default,
impl<T, U> CoerceUnsized<Cell<U>> for Cell<T> where
T: CoerceUnsized<U>,
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T: CoerceUnsized<U>,
impl<T> Send for Cell<T> where
T: Send + ?Sized,
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T: Send + ?Sized,
impl<T> Ord for Cell<T> where
T: Copy + Ord,
1.10.0[src]
T: Copy + Ord,
Auto Trait Implementations
impl<T: ?Sized> UnwindSafe for Cell<T> where
T: UnwindSafe,
T: UnwindSafe,
impl<T> !RefUnwindSafe for Cell<T>
impl<T: ?Sized> Unpin for Cell<T> where
T: Unpin,
T: Unpin,
Blanket Implementations
impl<T> From<T> for T
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impl<T, U> TryFrom<U> for T where
U: Into<T>,
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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>
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impl<T, U> Into<U> for T where
U: From<T>,
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U: From<T>,
impl<T, U> TryInto<U> for T where
U: TryFrom<T>,
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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>
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impl<T> Borrow<T> for T where
T: ?Sized,
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T: ?Sized,
impl<T> BorrowMut<T> for T where
T: ?Sized,
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T: ?Sized,
ⓘImportant traits for &'_ mut Ffn borrow_mut(&mut self) -> &mut T
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impl<T> Any for T where
T: 'static + ?Sized,
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T: 'static + ?Sized,
impl<T> ToOwned for T where
T: Clone,
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T: Clone,