alloc::task::Poll - Rust
Description: API documentation for the Rust `Poll` enum in crate `alloc`.
Keywords: rust, rustlang, rust-lang, Poll

# [−][src]Enum alloc::task::Poll

    pub enum Poll<T> {
        Ready(T),
        Pending,
    }

🔬 This is a nightly-only experimental API. (`futures_api` #50547)

futures in libcore are unstable

Indicates whether a value is available or if the current task has been scheduled to receive a wakeup instead.

## Variants

`Ready(T)`
🔬 This is a nightly-only experimental API. (`futures_api` #50547)

futures in libcore are unstable

Represents that a value is immediately ready.

`Pending`
🔬 This is a nightly-only experimental API. (`futures_api` #50547)

futures in libcore are unstable

Represents that a value is not ready yet.

When a function returns `Pending`, the function must also ensure that the current task is scheduled to be awoken when progress can be made.

## Methods

###

`impl<T> Poll<T>`

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####

`pub fn map<U, F>(self, f: F) -> Poll<U> where F: FnOnce(T) -> U,`

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🔬 This is a nightly-only experimental API. (`futures_api` #50547)

futures in libcore are unstable

Change the ready value of this `Poll` with the closure provided

####

`pub fn is_ready(&self) -> bool`

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🔬 This is a nightly-only experimental API. (`futures_api` #50547)

futures in libcore are unstable

Returns whether this is `Poll::Ready`

####

`pub fn is_pending(&self) -> bool`

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🔬 This is a nightly-only experimental API. (`futures_api` #50547)

futures in libcore are unstable

Returns whether this is `Poll::Pending`

###

`impl<T, E> Poll<Result<T, E>>`

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####

`pub fn map_ok<U, F>(self, f: F) -> Poll<Result<U, E>> where F: FnOnce(T) -> U,`

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🔬 This is a nightly-only experimental API. (`futures_api` #50547)

futures in libcore are unstable

Change the success value of this `Poll` with the closure provided

####

`pub fn map_err<U, F>(self, f: F) -> Poll<Result<T, U>> where F: FnOnce(E) -> U,`

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🔬 This is a nightly-only experimental API. (`futures_api` #50547)

futures in libcore are unstable

Change the error value of this `Poll` with the closure provided

## Trait Implementations

###

`impl<T> Copy for Poll<T> where T: Copy,`

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###

`impl<T, E> Try for Poll<Result<T, E>>`

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#### `type Ok = Poll<T>`

🔬 This is a nightly-only experimental API. (`try_trait` #42327)

The type of this value when viewed as successful.

#### `type Error = E`

🔬 This is a nightly-only experimental API. (`try_trait` #42327)

The type of this value when viewed as failed.

####

`fn into_result( self ) -> Result<<Poll<Result<T, E>> as Try>::Ok, <Poll<Result<T, E>> as Try>::Error>`

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🔬 This is a nightly-only experimental API. (`try_trait` #42327)

Applies the "?" operator. A return of `Ok(t)` means that the execution should continue normally, and the result of `?` is the value `t`. A return of `Err(e)` means that execution should branch to the innermost enclosing `catch`, or return from the function. Read more

####

`fn from_error(e: <Poll<Result<T, E>> as Try>::Error) -> Poll<Result<T, E>>`

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🔬 This is a nightly-only experimental API. (`try_trait` #42327)

Wrap an error value to construct the composite result. For example, `Result::Err(x)` and `Result::from_error(x)` are equivalent. Read more

####

`fn from_ok(x: <Poll<Result<T, E>> as Try>::Ok) -> Poll<Result<T, E>>`

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🔬 This is a nightly-only experimental API. (`try_trait` #42327)

Wrap an OK value to construct the composite result. For example, `Result::Ok(x)` and `Result::from_ok(x)` are equivalent. Read more

###

`impl<T, E> Try for Poll<Option<Result<T, E>>>`

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#### `type Ok = Poll<Option<T>>`

🔬 This is a nightly-only experimental API. (`try_trait` #42327)

The type of this value when viewed as successful.

#### `type Error = E`

🔬 This is a nightly-only experimental API. (`try_trait` #42327)

The type of this value when viewed as failed.

####

`fn into_result( self ) -> Result<<Poll<Option<Result<T, E>>> as Try>::Ok, <Poll<Option<Result<T, E>>> as Try>::Error>`

[src]

🔬 This is a nightly-only experimental API. (`try_trait` #42327)

Applies the "?" operator. A return of `Ok(t)` means that the execution should continue normally, and the result of `?` is the value `t`. A return of `Err(e)` means that execution should branch to the innermost enclosing `catch`, or return from the function. Read more

####

`fn from_error( e: <Poll<Option<Result<T, E>>> as Try>::Error ) -> Poll<Option<Result<T, E>>>`

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🔬 This is a nightly-only experimental API. (`try_trait` #42327)

Wrap an error value to construct the composite result. For example, `Result::Err(x)` and `Result::from_error(x)` are equivalent. Read more

####

`fn from_ok( x: <Poll<Option<Result<T, E>>> as Try>::Ok ) -> Poll<Option<Result<T, E>>>`

[src]

🔬 This is a nightly-only experimental API. (`try_trait` #42327)

Wrap an OK value to construct the composite result. For example, `Result::Ok(x)` and `Result::from_ok(x)` are equivalent. Read more

###

`impl<T> Hash for Poll<T> where T: Hash,`

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####

`fn hash<__HT>(&self, state: &mut __HT) where __HT: Hasher,`

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Feeds this value into the given [`Hasher`]. Read more

####

`fn hash_slice<H>(data: &[Self], state: &mut H) where H: Hasher,`

1.3.0
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Feeds a slice of this type into the given [`Hasher`]. Read more

###

`impl<T> From<T> for Poll<T>`

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####

`fn from(t: T) -> Poll<T>`

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Performs the conversion.

###

`impl<T> Eq for Poll<T> where T: Eq,`

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###

`impl<T> Clone for Poll<T> where T: Clone,`

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####

`fn clone(&self) -> Poll<T>`

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Returns a copy of the value. Read more

####

`fn clone_from(&mut self, source: &Self)`

1.0.0
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Performs copy-assignment from `source`. Read more

###

`impl<T> Debug for Poll<T> where T: Debug,`

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####

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

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Formats the value using the given formatter. Read more

###

`impl<T> PartialEq<Poll<T>> for Poll<T> where T: PartialEq<T>,`

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####

`fn eq(&self, other: &Poll<T>) -> bool`

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

####

`fn ne(&self, other: &Poll<T>) -> bool`

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This method tests for `!=`.

###

`impl<T> Ord for Poll<T> where T: Ord,`

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####

`fn cmp(&self, other: &Poll<T>) -> Ordering`

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This method returns an `Ordering` between `self` and `other`. Read more

####

`fn max(self, other: Self) -> Self`

1.21.0
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Compares and returns the maximum of two values. Read more

####

`fn min(self, other: Self) -> Self`

1.21.0
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Compares and returns the minimum of two values. Read more

###

`impl<T> PartialOrd<Poll<T>> for Poll<T> where T: PartialOrd<T>,`

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####

`fn partial_cmp(&self, other: &Poll<T>) -> Option<Ordering>`

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This method returns an ordering between `self` and `other` values if one exists. Read more

####

`fn lt(&self, other: &Poll<T>) -> bool`

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This method tests less than (for `self` and `other`) and is used by the `<` operator. Read more

####

`fn le(&self, other: &Poll<T>) -> bool`

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This method tests less than or equal to (for `self` and `other`) and is used by the `<=` operator. Read more

####

`fn gt(&self, other: &Poll<T>) -> bool`

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This method tests greater than (for `self` and `other`) and is used by the `>` operator. Read more

####

`fn ge(&self, other: &Poll<T>) -> bool`

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This method tests greater than or equal to (for `self` and `other`) and is used by the `>=` operator. Read more

## Auto Trait Implementations

###

`impl<T> Send for Poll<T> where T: Send,`

###

`impl<T> Sync for Poll<T> where T: Sync,`

## Blanket Implementations

###

`impl<T> ToOwned for T where T: Clone,`

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#### `type Owned = T`

####

`fn to_owned(&Self) -> T`

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Creates owned data from borrowed data, usually by cloning. Read more

####

`fn clone_into(&Self, &mut T)`

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🔬 This is a nightly-only experimental API. (`toowned_clone_into` #41263)

recently added

Uses borrowed data to replace owned data, usually by cloning. Read more

###

`impl<T> From for T`

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####

`fn from(t: T) -> T`

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Performs the conversion.

###

`impl<T, U> TryFrom for T where T: From<U>,`

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#### `type Error = !`

🔬 This is a nightly-only experimental API. (`try_from` #33417)

The type returned in the event of a conversion error.

####

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

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🔬 This is a nightly-only experimental API. (`try_from` #33417)

Performs the conversion.

###

`impl<T, U> TryInto for T where U: TryFrom<T>,`

[src]

#### `type Error = <U as TryFrom<T>>::Error`

🔬 This is a nightly-only experimental API. (`try_from` #33417)

The type returned in the event of a conversion error.

####

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

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🔬 This is a nightly-only experimental API. (`try_from` #33417)

Performs the conversion.

###

`impl<T, U> Into for T where U: From<T>,`

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####

`fn into(self) -> U`

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Performs the conversion.

###

`impl<T> Borrow for T where T: ?Sized,`

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####

`fn borrow(&self) -> &T`

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Immutably borrows from an owned value. Read more

###

`impl<T> BorrowMut for T where T: ?Sized,`

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####

`fn borrow_mut(&mut self) -> &mut T`

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Mutably borrows from an owned value. Read more

###

`impl<T> Any for T where T: 'static + ?Sized,`

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####

`fn get_type_id(&self) -> TypeId`

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🔬 This is a nightly-only experimental API. (`get_type_id` #27745)

this method will likely be replaced by an associated static

Gets the `TypeId` of `self`. Read more

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