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38 lines
1.4 KiB
Plaintext
38 lines
1.4 KiB
Plaintext
// The core of async is the `Future` trait, which defines some asynchronous computation
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// that may eventually yield a value.
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//
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// For more info, see https://doc.rust-lang.org/stable/std/future/trait.Future.html
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// Functions can be marked `async` to indicate that they return a type implementing `Future`.
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// The function signatures below are analogous.
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async fn do_work() -> String { ... }
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fn do_work() -> impl Future<Output = String> { ... }
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// To run a future, we can add a package that provides an async runtime, since Rust does
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// not come with one in the standard library. An asynchronous runtime schedules futures
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// and continuously polls them to completion. Here, we'll use tokio, a mature and
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// battle-tested library.
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// in Cargo.toml
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tokio = { version = "0.2.22", features = ["full"] }
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// Now we can spawn futures on a runtime.
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fn main() {
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let mut runtime = tokio::runtime::Runtime::new().unwrap();
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// `block_on` will block the current thread until the given task completes
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runtime.block_on(async {
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// Now we're in a worker thread
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// Futures can be executed using `.await`
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let my_string = do_work().await;
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});
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}
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// We can also use a macro to make this much more compact.
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#[tokio::main]
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async fn main() {
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let my_string = do_work().await;
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}
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// See https://docs.rs/tokio for more information on tokio.
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// See https://docs.rs/futures for more tools on working with futures.
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