diff --git a/src/libcore/future/future.rs b/src/libcore/future/future.rs index ea54b5a66996a..e1ab67873a025 100644 --- a/src/libcore/future/future.rs +++ b/src/libcore/future/future.rs @@ -18,9 +18,9 @@ use crate::task::{Context, Poll}; /// The core method of future, `poll`, *attempts* to resolve the future into a /// final value. This method does not block if the value is not ready. Instead, /// the current task is scheduled to be woken up when it's possible to make -/// further progress by `poll`ing again. The wake up is performed using -/// the `waker` argument of the `poll()` method, which is a handle for waking -/// up the current task. +/// further progress by `poll`ing again. The `context` passed to the `poll` +/// method can provide a `Waker`, which is a handle for waking up the current +/// task. /// /// When using a future, you generally won't call `poll` directly, but instead /// `await!` the value. @@ -49,13 +49,13 @@ pub trait Future { /// For example, a future waiting for a socket to become /// readable would call `.clone()` on the [`Waker`] and store it. /// When a signal arrives elsewhere indicating that the socket is readable, - /// `[Waker::wake]` is called and the socket future's task is awoken. + /// [`Waker::wake`] is called and the socket future's task is awoken. /// Once a task has been woken up, it should attempt to `poll` the future /// again, which may or may not produce a final value. /// - /// Note that on multiple calls to `poll`, only the most recent - /// [`Waker`] passed to `poll` should be scheduled to receive a - /// wakeup. + /// Note that on multiple calls to `poll`, only the [`Waker`] from the + /// [`Context`] passed to the most recent call should be scheduled to + /// receive a wakeup. /// /// # Runtime characteristics /// @@ -77,15 +77,15 @@ pub trait Future { /// thread pool (or something similar) to ensure that `poll` can return /// quickly. /// - /// An implementation of `poll` may also never cause memory unsafety. - /// /// # Panics /// - /// Once a future has completed (returned `Ready` from `poll`), - /// then any future calls to `poll` may panic, block forever, or otherwise - /// cause any kind of bad behavior except causing memory unsafety. - /// The `Future` trait itself provides no guarantees about the behavior - /// of `poll` after a future has completed. + /// Once a future has completed (returned `Ready` from `poll`), calling its + /// `poll` method again may panic, block forever, or cause other kinds of + /// problems; the `Future` trait places no requirements on the effects of + /// such a call. However, as the `poll` method is not marked `unsafe`, + /// Rust's usual rules apply: calls must never cause undefined behavior + /// (memory corruption, incorrect use of `unsafe` functions, or the like), + /// regardless of the future's state. /// /// [`Poll::Pending`]: ../task/enum.Poll.html#variant.Pending /// [`Poll::Ready(val)`]: ../task/enum.Poll.html#variant.Ready