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added playground links to show problem using thread park/unpark

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Carl Fredrik Samson
2020-04-14 00:33:34 +02:00
parent 08b155698c
commit 2fc79a9e03
7 changed files with 38 additions and 20 deletions
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src/6_future_example.md
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@@ -264,9 +264,9 @@ without passing around a reference.
> ### Why using thread park/unpark is a bad idea for a library
>
> It could deadlock easily since anyone could get a handle to the `executor thread`
> and call park/unpark on our thread or we could have a race condition where the
> future resolves and calls `wake` before we have time to go to sleep in our
> executor. We'll se how we can fix this at the end of this chapter.
> and call park/unpark on our thread. I've made [an example with comments on the
> playground](https://play.rust-lang.org/?version=stable&mode=debug&edition=2018&gist=b2343661fe3d271c91c6977ab8e681d0) that showcases how such an error could occur. You can also read a bit more about this in [issue 2010](https://github.com/rust-lang/futures-rs/pull/2010)
> in the futures crate.
## The Reactor
@@ -821,7 +821,13 @@ fn mywaker_wake(s: &MyWaker) {
}
```
And that's really all there is to it. The next chapter shows our finished code with this
And that's really all there is to it.
> If you checked out the playground link that showcased how park/unpark could [cause subtle
> problems](https://play.rust-lang.org/?version=stable&mode=debug&edition=2018&gist=b2343661fe3d271c91c6977ab8e681d0)
> you can [check out this example](https://play.rust-lang.org/?version=stable&mode=debug&edition=2018&gist=bebef0f8a8ce6a9d0d32442cc8381595) which shows how our final version avoids this problem.
The next chapter shows our finished code with this
improvement which you can explore further if you wish.
[mio]: https://github.com/tokio-rs/mio