Struct tokio::sync::watch::Ref

source ·
pub struct Ref<'a, T> { /* private fields */ }
Available on crate feature sync only.
Expand description

Returns a reference to the inner value.

Outstanding borrows hold a read lock on the inner value. This means that long lived borrows could cause the produce half to block. It is recommended to keep the borrow as short lived as possible.

The priority policy of the lock is dependent on the underlying lock implementation, and this type does not guarantee that any particular policy will be used. In particular, a producer which is waiting to acquire the lock in send might or might not block concurrent calls to borrow, e.g.:

Potential deadlock example
// Task 1 (on thread A)    |  // Task 2 (on thread B)
let _ref1 = rx.borrow();   |
                           |  // will block
                           |  let _ = tx.send(());
// may deadlock            |
let _ref2 = rx.borrow();   |

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The resulting type after dereferencing.
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