Struct `RawWakerVTable`

struct RawWakerVTable { ... }

A virtual function pointer table (vtable) that specifies the behavior of a RawWaker.

The pointer passed to all functions inside the vtable is the data pointer from the enclosing RawWaker object.

The functions inside this struct are only intended to be called on the data pointer of a properly constructed RawWaker object from inside the RawWaker implementation. Calling one of the contained functions using any other data pointer will cause undefined behavior.

Note that while this type implements PartialEq, comparing function pointers, and hence comparing structs like this that contain function pointers, is unreliable: pointers to the same function can compare inequal (because functions are duplicated in multiple codegen units), and pointers to different functions can compare equal (since identical functions can be deduplicated within a codegen unit).

Thread safety

If the RawWaker will be used to construct a Waker then these functions must all be thread-safe (even though RawWaker is ![Send] + ![Sync]). This is because Waker is [Send] + [Sync], and it may be moved to arbitrary threads or invoked by & reference. For example, this means that if the clone and drop functions manage a reference count, they must do so atomically.

However, if the RawWaker will be used to construct a LocalWaker instead, then these functions don't need to be thread safe. This means that ![Send] + ![Sync] data can be stored in the data pointer, and reference counting does not need any atomic synchronization. This is because LocalWaker is not thread safe itself, so it cannot be sent across threads.

Implementations

`impl RawWakerVTable`

const fn new(clone: unsafe fn(_: *const ()) -> RawWaker, wake: unsafe fn(_: *const ()), wake_by_ref: unsafe fn(_: *const ()), drop: unsafe fn(_: *const ())) -> Self

Creates a new RawWakerVTable from the provided clone, wake, wake_by_ref, and drop functions.

`clone`

This function will be called when the RawWaker gets cloned, e.g. when the Waker/LocalWaker in which the RawWaker is stored gets cloned.

The implementation of this function must retain all resources that are required for this additional instance of a RawWaker and associated task. Calling wake on the resulting RawWaker should result in a wakeup of the same task that would have been awoken by the original RawWaker.

`wake`

This function will be called when wake is called on the Waker. It must wake up the task associated with this RawWaker.

The implementation of this function must make sure to release any resources that are associated with this instance of a RawWaker and associated task.

`wake_by_ref`

This function will be called when wake_by_ref is called on the Waker. It must wake up the task associated with this RawWaker.

This function is similar to wake, but must not consume the provided data pointer.

`drop`

This function will be called when a Waker/LocalWaker gets dropped.

The implementation of this function must make sure to release any resources that are associated with this instance of a RawWaker and associated task.

`impl Clone for RawWakerVTable`

fn clone(self: &Self) -> RawWakerVTable

`impl Copy for RawWakerVTable`

`impl Debug for RawWakerVTable`

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

`impl Freeze for RawWakerVTable`

`impl PartialEq for RawWakerVTable`

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

`impl RefUnwindSafe for RawWakerVTable`

`impl Send for RawWakerVTable`

`impl StructuralPartialEq for RawWakerVTable`

`impl Sync for RawWakerVTable`

`impl Unpin for RawWakerVTable`

`impl UnsafeUnpin for RawWakerVTable`

`impl UnwindSafe for RawWakerVTable`

`impl<T> Any for RawWakerVTable`

fn type_id(self: &Self) -> TypeId

`impl<T> Borrow for RawWakerVTable`

fn borrow(self: &Self) -> &T

`impl<T> BorrowMut for RawWakerVTable`

fn borrow_mut(self: &mut Self) -> &mut T

`impl<T> CloneToUninit for RawWakerVTable`

unsafe fn clone_to_uninit(self: &Self, dest: *mut u8)

`impl<T> From for RawWakerVTable`

fn from(t: T) -> T: Returns the argument unchanged.

`impl<T, U> Into for RawWakerVTable`

fn into(self: Self) -> U

Calls U::from(self).

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

`impl<T, U> TryFrom for RawWakerVTable`

fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

`impl<T, U> TryInto for RawWakerVTable`

fn try_into(self: Self) -> Result<U, <U as TryFrom<T>>::Error>