1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65
//! Asynchronous values. //! //! ## Base Futures Concurrency //! //! Often it's desireable to await multiple futures as if it was a single //! future. The `join` family of operations converts multiple futures into a //! single future that returns all of their outputs. The `select` family of //! operations converts multiple future into a single future that returns the //! first output. //! //! For operating on futures the following macros can be used: //! //! | Name | Return signature | When does it return? | //! | --- | --- | --- | //! | `future::join` | `(T1, T2)` | Wait for all to complete //! | `future::select` | `T` | Return on first value //! //! ## Fallible Futures Concurrency //! //! For operating on futures that return `Result` additional `try_` variants of //! the macros mentioned before can be used. These macros are aware of `Result`, //! and will behave slightly differently from their base variants. //! //! In the case of `try_join`, if any of the futures returns `Err` all //! futures are dropped and an error is returned. This is referred to as //! "short-circuiting". //! //! In the case of `try_select`, instead of returning the first future that //! completes it returns the first future that _successfully_ completes. This //! means `try_select` will keep going until any one of the futures returns //! `Ok`, or _all_ futures have returned `Err`. //! //! However sometimes it can be useful to use the base variants of the macros //! even on futures that return `Result`. Here is an overview of operations that //! work on `Result`, and their respective semantics: //! //! | Name | Return signature | When does it return? | //! | --- | --- | --- | //! | `future::join` | `(Result<T, E>, Result<T, E>)` | Wait for all to complete //! | `future::try_join` | `Result<(T1, T2), E>` | Return on first `Err`, wait for all to complete //! | `future::select` | `Result<T, E>` | Return on first value //! | `future::try_select` | `Result<T, E>` | Return on first `Ok`, reject on last Err #[doc(inline)] pub use async_macros::{join, try_join}; pub use future::Future; pub use pending::pending; pub use poll_fn::poll_fn; pub use ready::ready; pub use timeout::{timeout, TimeoutError}; pub(crate) mod future; mod pending; mod poll_fn; mod ready; mod timeout; cfg_unstable! { #[doc(inline)] pub use async_macros::{select, try_select}; pub use into_future::IntoFuture; mod into_future; }