我想在foo执行程序的current_thread内生成一个任务:
extern crate futures; // version 0.1
extern crate tokio;
use futures::future::lazy;
use std::{thread, time};
use tokio::executor::current_thread::CurrentThread;
fn foo() {
tokio::spawn(lazy(|| {
println!("In foo!");
Ok(())
}));
}
fn main() {
let mut current_thread = CurrentThread::new();
current_thread.spawn(lazy(|| {
loop {
println!("In spawn!");
foo();
thread::sleep(time::Duration::from_secs(1));
}
Ok(())
}));
current_thread.run().unwrap();
}
当我运行它时，它失败并显示:
In spawn!
thread 'main' panicked at 'called `Result::unwrap()` on an `Err` value: SpawnError { is_shutdown: true }', libcore/result.rs:945:5
stack backtrace:
0: 0x10879438f - std::sys::unix::backtrace::tracing::imp::unwind_backtrace::hd4a234eb73c9eb11
at libstd/sys/unix/backtrace/tracing/gcc_s.rs:49
1: 0x108788b9d - std::sys_common::backtrace::print::h686165a0aebbb1f5
at libstd/sys_common/backtrace.rs:71
at libstd/sys_common/backtrace.rs:59
2: 0x108797043 - std::panicking::default_hook::{{closure}}::h25aacbcb8a8273d9
at libstd/panicking.rs:205
3: 0x108796dcc - std::panicking::default_hook::h036425f579a26a8f
at libstd/panicking.rs:221
4: 0x10879758b - <std::panicking::begin_panic::PanicPayload<A> as core::panic::BoxMeUp>::get::hac9fda42d0999bf5
at libstd/panicking.rs:457
5: 0x1087971c0 - std::panicking::try::do_call::h8b3a10ecb1a21334
at libstd/panicking.rs:344
6: 0x108797182 - std::panicking::try::do_call::h8b3a10ecb1a21334
at libstd/panicking.rs:322
7: 0x1087cbac5 - <&'a T as core::fmt::Display>::fmt::h2e38aa9ebf1dda6d
at libcore/panicking.rs:71
8: 0x108771405 - core::result::unwrap_failed::h111a0aed60721615
at /Users/travis/build/rust-lang/rust/src/libcore/macros.rs:26
9: 0x10877110b - <core::result::Result<T, E>>::unwrap::h1b36496d5b4f78f0
at /Users/travis/build/rust-lang/rust/src/libcore/result.rs:782
10: 0x108771ba6 - tokio_executor::global::spawn::h95932f8a5d0c0373
at /tmp/registry/src/github.com-1ecc6299db9ec823/tokio-executor-0.1.2/src/global.rs:128
11: 0x108771b26 - tokio::executor::spawn::hbdc3654dcb691a15
at /tmp/registry/src/github.com-1ecc6299db9ec823/tokio-0.1.6/src/executor/mod.rs:207
12: 0x108772a5a - ox::foo::h1a20773fe06f38f5
at src/main.rs:9
13: 0x1087729e3 - ox::main::{{closure}}::ha045cd464fd2bcd2
at src/main.rs:20
14: 0x108770de0 - <futures::future::lazy::Lazy<F, R>>::get::h6d01f86e63eb0ae6
at /tmp/registry/src/github.com-1ecc6299db9ec823/futures-0.1.21/src/future/lazy.rs:64
15: 0x108770f54 - <futures::future::lazy::Lazy<F, R> as futures::future::Future>::poll::he4dbb0cba4734268
at /tmp/registry/src/github.com-1ecc6299db9ec823/futures-0.1.21/src/future/lazy.rs:82
16: 0x1087765a4 - core::fmt::Arguments::new_v1_formatted::h535b215c9c95b52a
at /tmp/registry/src/github.com-1ecc6299db9ec823/futures-0.1.21/src/future/mod.rs:113
17: 0x1087750a4 - <futures::task_impl::Spawn<T>>::poll_future_notify::{{closure}}::he965765a8e172c4b
at /tmp/registry/src/github.com-1ecc6299db9ec823/futures-0.1.21/src/task_impl/mod.rs:289
18: 0x10877520a - <futures::task_impl::Spawn<T>>::enter::{{closure}}::hc5d84c8a0c9b9541
at /tmp/registry/src/github.com-1ecc6299db9ec823/futures-0.1.21/src/task_impl/mod.rs:363
19: 0x108774dc8 - futures::task_impl::std::set::h6d292679eb1abcd6
at /tmp/registry/src/github.com-1ecc6299db9ec823/futures-0.1.21/src/task_impl/std/mod.rs:78
20: 0x1087751a7 - <futures::task_impl::Spawn<T>>::enter::h19b2ea99bdf79995
at /tmp/registry/src/github.com-1ecc6299db9ec823/futures-0.1.21/src/task_impl/mod.rs:363
21: 0x108775039 - <futures::task_impl::Spawn<T>>::poll_future_notify::hf216aece3ea15c32
at /tmp/registry/src/github.com-1ecc6299db9ec823/futures-0.1.21/src/task_impl/mod.rs:289
22: 0x108773e03 - <tokio::executor::current_thread::scheduler::Scheduled<'a, U>>::tick::haebb55271ba68f7f
at /tmp/registry/src/github.com-1ecc6299db9ec823/tokio-0.1.6/src/executor/current_thread/scheduler.rs:352
23: 0x108773d8c - <tokio::executor::current_thread::scheduler::Scheduler<U>>::tick::{{closure}}::h0fdf80d08ed0341a
at /tmp/registry/src/github.com-1ecc6299db9ec823/tokio-0.1.6/src/executor/current_thread/scheduler.rs:332
24: 0x1087720fc - <tokio::executor::current_thread::Borrow<'a, U>>::enter::{{closure}}::{{closure}}::hc3a2b045d8dbd69f
at /tmp/registry/src/github.com-1ecc6299db9ec823/tokio-0.1.6/src/executor/current_thread/mod.rs:688
25: 0x108771c7f - tokio::executor::current_thread::CurrentRunner::set_spawn::h796df298bd44491f
at /tmp/registry/src/github.com-1ecc6299db9ec823/tokio-0.1.6/src/executor/current_thread/mod.rs:720
26: 0x10877209c - <tokio::executor::current_thread::Borrow<'a, U>>::enter::{{closure}}::hf2160ea4bc6cb70d
at /tmp/registry/src/github.com-1ecc6299db9ec823/tokio-0.1.6/src/executor/current_thread/mod.rs:687
27: 0x108771887 - <std::thread::local::LocalKey<T>>::try_with::h07c3b54d23ac7bcf
at /Users/travis/build/rust-lang/rust/src/libstd/thread/local.rs:294
28: 0x1087716b4 - <std::thread::local::LocalKey<T>>::with::h8a95d51541a57481
at /Users/travis/build/rust-lang/rust/src/libstd/thread/local.rs:248
29: 0x108771fda - <tokio::executor::current_thread::Borrow<'a, U>>::enter::hd84e35a45b8c5f10
at /tmp/registry/src/github.com-1ecc6299db9ec823/tokio-0.1.6/src/executor/current_thread/mod.rs:686
30: 0x108773c6d - <tokio::executor::current_thread::scheduler::Scheduler<U>>::tick::hc6a4d68c4ca62da1
at /tmp/registry/src/github.com-1ecc6299db9ec823/tokio-0.1.6/src/executor/current_thread/scheduler.rs:332
31: 0x1087724bd - <tokio::executor::current_thread::Entered<'a, P>>::tick::h806caa14d1fda0e2
at /tmp/registry/src/github.com-1ecc6299db9ec823/tokio-0.1.6/src/executor/current_thread/mod.rs:572
32: 0x1087721ac - <tokio::executor::current_thread::Entered<'a, P>>::run_timeout2::hacdc210a9580db1b
at /tmp/registry/src/github.com-1ecc6299db9ec823/tokio-0.1.6/src/executor/current_thread/mod.rs:541
33: 0x108772450 - <tokio::executor::current_thread::Entered<'a, P>>::run::h98ebc98ef8f09a85
at /tmp/registry/src/github.com-1ecc6299db9ec823/tokio-0.1.6/src/executor/current_thread/mod.rs:484
34: 0x108771e04 - <tokio::executor::current_thread::CurrentThread<P>>::run::h023b6fbff627efb0
at /tmp/registry/src/github.com-1ecc6299db9ec823/tokio-0.1.6/src/executor/current_thread/mod.rs:356
35: 0x108772ac0 - ox::main::h5fd6c3ac8eb3383f
at src/main.rs:25
36: 0x108772cc1 - std::rt::lang_start::{{closure}}::h8d7d3864a0a638c3
at /Users/travis/build/rust-lang/rust/src/libstd/rt.rs:74
37: 0x1087970e7 - std::panicking::try::do_call::h8b3a10ecb1a21334
at libstd/rt.rs:59
at libstd/panicking.rs:304
38: 0x1087a2cde - panic_unwind::dwarf::eh::read_encoded_pointer::hcabc31a4d46081c4
at libpanic_unwind/lib.rs:105
39: 0x10878fd00 - std::sys_common::bytestring::debug_fmt_bytestring::h020ca4453b64bdbd
at libstd/panicking.rs:283
at libstd/panic.rs:361
at libstd/rt.rs:58
40: 0x108772ca1 - std::rt::lang_start::h14c96d0aa9f67dbd
at /Users/travis/build/rust-lang/rust/src/libstd/rt.rs:74
41: 0x108772b14 - ox::main::h5fd6c3ac8eb3383f
我尝试将
current_thread传递给foo，但是无法编译。是否可以这样做，如果可以，怎么做？ 最佳答案
对的，这是可能的。 Tokio提供documentation on how to use current_thread :
您的特定问题是您没有在当前线程上生成任务:
fn foo() {
tokio::spawn(lazy(|| {
// ^^^^^^^^^^^^
相反，这应该是
fn foo() {
current_thread::spawn(lazy(|| {
// ^^^^^^^^^^^^^^^^^^^^^
但是，我不认为此代码会实际打印
In foo!，因为外部循环永远不会创建会阻塞的 future ，因此执行者没有理由再看任何其他 future 。