Struct std::sync::WeakUnstable

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

A weak pointer to an Arc.

Weak pointers will not keep the data inside of the Arc alive, and can be used to break cycles between Arc pointers.

Methods

impl<T> Weak<T> where T: Send, T: Sync

fn upgrade(&self) -> Option<Arc<T>>

Upgrades a weak reference to a strong reference.

Upgrades the Weak<T> reference to an Arc<T>, if possible.

Returns None if there were no strong references and the data was destroyed.

Examples

fn main() { use std::sync::Arc; let five = Arc::new(5); let weak_five = five.downgrade(); let strong_five: Option<Arc<_>> = weak_five.upgrade(); }

use std::sync::Arc;

let five = Arc::new(5);

let weak_five = five.downgrade();

let strong_five: Option<Arc<_>> = weak_five.upgrade();

Trait Implementations

impl<T> Send for Weak<T> where T: Send, T: Sync

impl<T> Sync for Weak<T> where T: Send, T: Sync

impl<T> Clone for Weak<T> where T: Send, T: Sync

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

Makes a clone of the Weak<T>.

This increases the weak reference count.

Examples

fn main() { use std::sync::Arc; let weak_five = Arc::new(5).downgrade(); weak_five.clone(); }

use std::sync::Arc;

let weak_five = Arc::new(5).downgrade();

weak_five.clone();

fn clone_from(&mut self, &Weak<T>)

impl<T> Drop for Weak<T> where T: Send, T: Sync

fn drop(&mut self)

Drops the Weak<T>.

This will decrement the weak reference count.

Examples

fn main() { use std::sync::Arc; { let five = Arc::new(5); let weak_five = five.downgrade(); // stuff drop(weak_five); // explicit drop } { let five = Arc::new(5); let weak_five = five.downgrade(); // stuff } // implicit drop }

use std::sync::Arc;

{
    let five = Arc::new(5);
    let weak_five = five.downgrade();

    // stuff

    drop(weak_five); // explicit drop
}
{
    let five = Arc::new(5);
    let weak_five = five.downgrade();

    // stuff

} // implicit drop