Struct futures::task::RawWaker

pub struct RawWaker { /* private fields */ }

A RawWaker allows the implementor of a task executor to create a Waker or a LocalWaker which provides customized wakeup behavior.

It consists of a data pointer and a virtual function pointer table (vtable) that customizes the behavior of the RawWaker.

RawWakers are unsafe to use. Implementing the Wake trait is a safe alternative that requires memory allocation.

Implementations

impl RawWaker

pub const fn new(data: *const (), vtable: &'static RawWakerVTable) -> RawWaker

Creates a new RawWaker from the provided data pointer and vtable.

The data pointer can be used to store arbitrary data as required by the executor. This could be e.g. a type-erased pointer to an Arc that is associated with the task. The value of this pointer will get passed to all functions that are part of the vtable as the first parameter.

It is important to consider that the data pointer must point to a thread safe type such as an [Arc]<T: Send + Sync> when used to construct a Waker. This restriction is lifted when constructing a LocalWaker, which allows using types that do not implement Send + Sync like [Rc]<T>.

The vtable customizes the behavior of a Waker which gets created from a RawWaker. For each operation on the Waker, the associated function in the vtable of the underlying RawWaker will be called.

pub fn data(&self) -> *const ()

🔬This is a nightly-only experimental API. (waker_getters)

Get the data pointer used to create this RawWaker.

pub fn vtable(&self) -> &'static RawWakerVTable

🔬This is a nightly-only experimental API. (waker_getters)

Get the vtable pointer used to create this RawWaker.

Trait Implementations

impl Debug for RawWaker

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

Formats the value using the given formatter.

impl<W> From<Arc<W>> for RawWaker

where W: Wake + Send + Sync + 'static,

fn from(waker: Arc<W>) -> RawWaker

Use a Wake-able type as a RawWaker.

No heap allocations or atomic operations are used for this conversion.

impl<W> From<Rc<W>> for RawWaker

where W: LocalWake + 'static,

fn from(waker: Rc<W>) -> RawWaker

Use a Wake-able type as a RawWaker.

No heap allocations or atomic operations are used for this conversion.

impl PartialEq for RawWaker

fn eq(&self, other: &RawWaker) -> bool

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

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

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl StructuralPartialEq for RawWaker