pub struct LocalKey<T> { /* private fields */ }
Expand description

A key for task-local data stored in a future’s task.

This type is generated by the task_local! macro and performs very similarly to the thread_local! macro and std::thread::LocalKey types. Data associated with a LocalKey<T> is stored inside of a future’s task, and the data is destroyed when the future is completed and the task is destroyed.

Task-local data can migrate between threads and hence requires a Send bound. Additionally, task-local data also requires the 'static bound to ensure it lives long enough. When a key is accessed for the first time the task’s data is initialized with the provided initialization expression to the macro.

Implementations

Access this task-local key, running the provided closure with a reference to the value.

This function will access this task-local key to retrieve the data associated with the current task and this key. If this is the first time this key has been accessed on this task, then the key will be initialized with the initialization expression provided at the time the task_local! macro was called.

The provided closure will be provided a shared reference to the underlying data associated with this task-local-key. The data itself is stored inside of the current task.

Panics

This function can possibly panic for a number of reasons:

  • If there is not a current task.
  • If the initialization expression is run and it panics
  • If the closure provided panics

Trait Implementations

Formats the value using the given formatter. Read more

Auto Trait Implementations

Blanket Implementations

Gets the TypeId of self. Read more

Immutably borrows from an owned value. Read more

Mutably borrows from an owned value. Read more

Returns the argument unchanged.

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

The type returned in the event of a conversion error.

Performs the conversion.

The type returned in the event of a conversion error.

Performs the conversion.