Struct std::cell::RefCell

pub struct RefCell<T> {
    // some fields omitted
}

A mutable memory location with dynamically checked borrow rules

See the module-level documentation for more.

Methods

impl<T> RefCell<T>

fn new(value: T) -> RefCell<T>

Creates a new RefCell containing value.

Examples

extern crate std; fn main() { use std::cell::RefCell; let c = RefCell::new(5); }

use std::cell::RefCell;

let c = RefCell::new(5);

fn into_inner(self) -> T

Consumes the RefCell, returning the wrapped value.

Examples

extern crate std; fn main() { use std::cell::RefCell; let c = RefCell::new(5); let five = c.into_inner(); }

use std::cell::RefCell;

let c = RefCell::new(5);

let five = c.into_inner();

fn borrow_state(&self) -> BorrowState

Unstable

Query the current state of this RefCell

The returned value can be dispatched on to determine if a call to borrow or borrow_mut would succeed.

fn borrow(&'a self) -> Ref<'a, T>

Immutably borrows the wrapped value.

The borrow lasts until the returned Ref exits scope. Multiple immutable borrows can be taken out at the same time.

Panics

Panics if the value is currently mutably borrowed.

Examples

extern crate std; fn main() { use std::cell::RefCell; let c = RefCell::new(5); let borrowed_five = c.borrow(); let borrowed_five2 = c.borrow(); }

use std::cell::RefCell;

let c = RefCell::new(5);

let borrowed_five = c.borrow();
let borrowed_five2 = c.borrow();

An example of panic:

extern crate std; fn main() { use std::cell::RefCell; use std::thread; let result = thread::spawn(move || { let c = RefCell::new(5); let m = c.borrow_mut(); let b = c.borrow(); // this causes a panic }).join(); assert!(result.is_err()); }

use std::cell::RefCell;
use std::thread;

let result = thread::spawn(move || {
   let c = RefCell::new(5);
   let m = c.borrow_mut();

   let b = c.borrow(); // this causes a panic
}).join();

assert!(result.is_err());

fn borrow_mut(&'a self) -> RefMut<'a, T>

Mutably borrows the wrapped value.

The borrow lasts until the returned RefMut exits scope. The value cannot be borrowed while this borrow is active.

Panics

Panics if the value is currently borrowed.

Examples

extern crate std; fn main() { use std::cell::RefCell; let c = RefCell::new(5); let borrowed_five = c.borrow_mut(); }

use std::cell::RefCell;

let c = RefCell::new(5);

let borrowed_five = c.borrow_mut();

An example of panic:

extern crate std; fn main() { use std::cell::RefCell; use std::thread; let result = thread::spawn(move || { let c = RefCell::new(5); let m = c.borrow(); let b = c.borrow_mut(); // this causes a panic }).join(); assert!(result.is_err()); }

use std::cell::RefCell;
use std::thread;

let result = thread::spawn(move || {
   let c = RefCell::new(5);
   let m = c.borrow();

   let b = c.borrow_mut(); // this causes a panic
}).join();

assert!(result.is_err());

unsafe fn as_unsafe_cell(&'a self) -> &'a UnsafeCell<T>

Unstable

Gets a reference to the underlying UnsafeCell.

This can be used to circumvent RefCell's safety checks.

This function is unsafe because UnsafeCell's field is public.

Trait Implementations

impl<T> Send for RefCell<T> where T: Send

impl<T> Clone for RefCell<T> where T: Clone

fn clone(&self) -> RefCell<T>

fn clone_from(&mut self, source: &Self)

impl<T> Default for RefCell<T> where T: Default

fn default() -> RefCell<T>

impl<T> PartialEq<RefCell<T>> for RefCell<T> where T: PartialEq<T>

fn eq(&self, other: &RefCell<T>) -> bool

fn ne(&self, other: &Rhs) -> bool

impl<T> Debug for RefCell<T> where T: Debug

fn fmt(&self, f: &mut Formatter) -> Result<(), Error>