我想出是否有可能 . 它似乎可能不是,因为它们显然不符合 Send
特征 .
以下代码演示了我正在尝试做的事情:
use std::{
sync::mpsc::{channel, Receiver, Sender},
thread,
};
trait Bar {
fn bar(&self);
}
struct Foo {
foo: i32,
}
impl Bar for Foo {
fn bar(&self) {
println!("foo: {}", self.foo);
}
}
fn main() {
let foo = Box::new(Foo { foo: 1 }) as Box<Bar>;
let (tx, rx): (Sender<Box<Bar>>, Receiver<Box<Bar>>) = channel();
thread::spawn(move || {
tx.send(foo).unwrap();
});
let sent = rx.recv().unwrap();
sent.bar();
}
此操作失败,并显示以下消息:
error[E0277]: `std::sync::mpsc::Sender<std::boxed::Box<Bar>>` cannot be shared between threads safely
--> src/main.rs:25:5
|
25 | thread::spawn(|| {
| ^^^^^^^^^^^^^ `std::sync::mpsc::Sender<std::boxed::Box<Bar>>` cannot be shared between threads safely
|
= help: the trait `std::marker::Sync` is not implemented for `std::sync::mpsc::Sender<std::boxed::Box<Bar>>`
= note: required because of the requirements on the impl of `std::marker::Send` for `&std::sync::mpsc::Sender<std::boxed::Box<Bar>>`
= note: required because it appears within the type `[closure@src/main.rs:25:19: 27:6 tx:&std::sync::mpsc::Sender<std::boxed::Box<Bar>>, foo:std::boxed::Box<Bar>]`
= note: required by `std::thread::spawn`
error[E0277]: the trait bound `Bar: std::marker::Send` is not satisfied
--> src/main.rs:25:5
|
25 | thread::spawn(|| {
| ^^^^^^^^^^^^^ `Bar` cannot be sent between threads safely
|
= help: the trait `std::marker::Send` is not implemented for `Bar`
= note: required because of the requirements on the impl of `std::marker::Send` for `std::ptr::Unique<Bar>`
= note: required because it appears within the type `std::boxed::Box<Bar>`
= note: required because it appears within the type `[closure@src/main.rs:25:19: 27:6 tx:&std::sync::mpsc::Sender<std::boxed::Box<Bar>>, foo:std::boxed::Box<Bar>]`
= note: required by `std::thread::spawn`
试图发送一个普通的,未装箱的特征对象会导致一堆其他错误,主要是抱怨不满足 Send + Sized
.
我不确定是否缺少's something I',但我得到的印象是没有办法说服编译器制作特征对象 Send
.
如果目前无法实现,目前是否有任何工作可以在将来实现这一目标?
1 回答
这是可能的 . 您可以将
Send
约束添加到特征对象,如下所示: