std::future::UnsafeFutureObj - Rust
Description: API documentation for the Rust `UnsafeFutureObj` trait in crate `std`.
Keywords: rust, rustlang, rust-lang, UnsafeFutureObj

# Trait std::future::UnsafeFutureObj[−][src]

    pub unsafe trait UnsafeFutureObj<'a, T>: 'a {
        fn into_raw(self) -> *mut ();
        unsafe fn poll(ptr: *mut (), cx: &mut Context) -> Poll<T>;
        unsafe fn drop(ptr: *mut ());
    }

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

futures in libcore are unstable

A custom implementation of a future trait object for `FutureObj`, providing a hand-rolled vtable.

This custom representation is typically used only in `no_std` contexts, where the default `Box`-based implementation is not available.

The implementor must guarantee that it is safe to call `poll` repeatedly (in a non-concurrent fashion) with the result of `into_raw` until `drop` is called.

## Required Methods

### `fn into_raw(self) -> *mut ()`

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

futures in libcore are unstable

Convert an owned instance into a (conceptually owned) void pointer.

### `unsafe fn poll(ptr: *mut (), cx: &mut Context) -> Poll<T>`

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

futures in libcore are unstable

Poll the future represented by the given void pointer.

# Safety

The trait implementor must guarantee that it is safe to repeatedly call `poll` with the result of `into_raw` until `drop` is called; such calls are not, however, allowed to race with each other or with calls to `drop`.

### `unsafe fn drop(ptr: *mut ())`

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

futures in libcore are unstable

Drops the future represented by the given void pointer.

# Safety

The trait implementor must guarantee that it is safe to call this function once per `into_raw` invocation; that call cannot race with other calls to `drop` or `poll`.

## Implementors

- `impl<'a, T, F> UnsafeFutureObj<'a, T> for PinMut<'a, F> where F: Future<Output = T> + 'a,` | [src]

- `impl<'a, T, F> UnsafeFutureObj<'a, T> for &'a mut F where F: Future<Output = T> + Unpin + 'a,` | [src]

- `impl<'a, T, F> UnsafeFutureObj<'a, T> for PinBox<F> where F: Future<Output = T> + 'a,` | [src]

- `impl<'a, T, F> UnsafeFutureObj<'a, T> for Box<F> where F: Future<Output = T> + 'a,` | [src]

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