我正在尝试对Rust中的进程使用异步/等待。我正在使用tokio和tokio-process：
#![feature(await_macro, async_await, futures_api)]
extern crate tokio;
extern crate tokio_process;
use std::process::Command;
use tokio_process::CommandExt;
fn main() {
tokio::run_async(main_async());
}
async fn main_async() {
let out = Command::new("echo")
.arg("hello")
.arg("world")
.output_async();
let s = await!(out);
}
这是我得到的错误：
error[E0277]: the trait bound `tokio_process::OutputAsync: std::future::Future` is not satisfied
--> src/main.rs:21:13
|
21 | let s = await!(out);
| ^^^^^^^^^^^ the trait `std::future::Future` is not implemented for `tokio_process::OutputAsync`
|
= note: required by `std::future::poll_with_tls_waker`
= note: this error originates in a macro outside of the current crate (in Nightly builds, run with -Z external-macro-backtrace for more info)
error[E0277]: the trait bound `tokio_process::OutputAsync: std::future::Future` is not satisfied
--> src/main.rs:21:13
|
21 | let s = await!(out);
| ^^^^^^^^^^^ the trait `std::future::Future` is not implemented for `tokio_process::OutputAsync`
|
= note: this error originates in a macro outside of the current crate (in Nightly builds, run with -Z external-macro-backtrace for more info)
我该如何正确处理？
Tokio 0.1和相关的板条箱]使用stable期货0.1条板箱实现。此板条箱的Future特征在概念上与标准库中Future特征的版本相似，但细节上有很大不同。async/ await语法围绕标准库中的特征版本构建。
尚未发布的Tokio 0.2和相关的板条箱是使用标准库Future实现的，正在重新制作以更好地支持async / await语法。
[dependencies]
tokio = "0.2.0-alpha.2"
tokio-process = "0.3.0-alpha.2"
use tokio_process::Command;
#[tokio::main]
async fn main() -> std::io::Result<()> {
let out = Command::new("echo")
.arg("hello")
.arg("world")
.output()
.await?;
let s = String::from_utf8_lossy(&out.stdout);
println!("{}", s);
Ok(())
}
$ cargo run
Finished dev [unoptimized + debuginfo] target(s) in 0.05s
Running `target/debug/tt`
hello world
经过测试：
对“ tokio async await”执行互联网搜索会导致使用恰当命名的板条箱tokio-async-await。本文记录了如何使Tokio能够参与不稳定的期货交易：
[dependencies]
tokio = { version = "0.1.15", features = ["async-await-preview"] }
tokio-process = "0.2.3"
在您的代码中，您必须在针对期货0.1板条箱和标准库中的特征而实现的Future之间进行转换。一种简单的方法是使用await宏的Tokio版本：
#![feature(await_macro, async_await, futures_api)]
use std::process::Command;
use tokio_process::CommandExt;
fn main() {
tokio::run_async(main_async());
}
async fn main_async() {
let out = Command::new("echo")
.arg("hello")
.arg("world")
.output_async();
let s = tokio::await!(out);
println!("{:?}", s);
}
$ cargo run
Finished dev [unoptimized + debuginfo] target(s) in 0.10s
Running `target/debug/oo`
Ok(Output { status: ExitStatus(ExitStatus(0)), stdout: "hello world\n", stderr: "" })
经过测试：
另请参见：