Struct core::cell::Cell1.0.0 [] [src]

pub struct Cell<T> { /* fields omitted */ }

A mutable memory location.

Examples

Here you can see how using Cell<T> allows to use mutable field inside immutable struct (which is also called '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, because my_struct is immutable
// my_struct.regular_field = new_value;

// WORKS, although `my_struct` is immutable, field `special_field` is mutable because it is Cell
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: Copy> Cell<T>
[src]

[src]

Returns a copy of the contained value.

Examples

use std::cell::Cell;

let c = Cell::new(5);

let five = c.get();Run

impl<T> Cell<T>
[src]

[src]

Creates a new Cell containing the given value.

Examples

use std::cell::Cell;

let c = Cell::new(5);Run

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

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

[src]

Sets the contained value.

Examples

use std::cell::Cell;

let c = Cell::new(5);

c.set(10);Run

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

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

1.17.0
[src]

Unwraps the value.

Examples

use std::cell::Cell;

let c = Cell::new(5);
let five = c.into_inner();

assert_eq!(five, 5);Run

impl<T: Default> Cell<T>
[src]

1.17.0
[src]

Takes the value of the cell, leaving Default::default() in its place.

Examples

use std::cell::Cell;

let c = Cell::new(5);
let five = c.take();

assert_eq!(five, 5);
assert_eq!(c.into_inner(), 0);Run

Trait Implementations

impl<T> Send for Cell<T> where
    T: Send
[src]

impl<T> !Sync for Cell<T>
[src]

impl<T: Copy> Clone for Cell<T>
[src]

[src]

Returns a copy of the value. Read more

[src]

Performs copy-assignment from source. Read more

impl<T: Default> Default for Cell<T>
[src]

[src]

Creates a Cell<T>, with the Default value for T.

impl<T: PartialEq + Copy> PartialEq for Cell<T>
[src]

[src]

This method tests for self and other values to be equal, and is used by ==. Read more

[src]

This method tests for !=.

impl<T: Eq + Copy> Eq for Cell<T>
1.2.0
[src]

impl<T: PartialOrd + Copy> PartialOrd for Cell<T>
1.10.0
[src]

[src]

This method returns an ordering between self and other values if one exists. Read more

[src]

This method tests less than (for self and other) and is used by the < operator. Read more

[src]

This method tests less than or equal to (for self and other) and is used by the <= operator. Read more

[src]

This method tests greater than (for self and other) and is used by the > operator. Read more

[src]

This method tests greater than or equal to (for self and other) and is used by the >= operator. Read more

impl<T: Ord + Copy> Ord for Cell<T>
1.10.0
[src]

[src]

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

1.21.0
[src]

Compares and returns the maximum of two values. Read more

1.21.0
[src]

Compares and returns the minimum of two values. Read more

impl<T> From<T> for Cell<T>
1.12.0
[src]

[src]

Performs the conversion.

impl<T: CoerceUnsized<U>, U> CoerceUnsized<Cell<U>> for Cell<T>
[src]

impl<T: CoerceUnsized<U>, U> CoerceUnsized<Cell<U>> for Cell<T>
[src]

impl<T: Copy + Debug> Debug for Cell<T>
[src]

[src]

Formats the value using the given formatter.