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authorliv <mokou@fastmail.com>2024-03-31 16:22:54 +0200
committerGitHub <noreply@github.com>2024-03-31 16:22:54 +0200
commitca07abf3dc1d436514f3ceb97e6edda0526f14cf (patch)
treed1201f3071c5a6094c99320f93cc953283da76f8
parent4e598572280451c884ec34669711804034f01c82 (diff)
parent842e341895690aa8d59aab42d6294994ef99d10f (diff)
Merge pull request #1929 from mo8it/threads2
threads2: simplify the exercise
-rw-r--r--exercises/20_threads/threads2.rs11
-rw-r--r--info.toml20
2 files changed, 13 insertions, 18 deletions
diff --git a/exercises/20_threads/threads2.rs b/exercises/20_threads/threads2.rs
index 62dad80..60d6824 100644
--- a/exercises/20_threads/threads2.rs
+++ b/exercises/20_threads/threads2.rs
@@ -18,7 +18,9 @@ struct JobStatus {
}
fn main() {
+ // TODO: `Arc` isn't enough if you want a **mutable** shared state
let status = Arc::new(JobStatus { jobs_completed: 0 });
+
let mut handles = vec![];
for _ in 0..10 {
let status_shared = Arc::clone(&status);
@@ -29,11 +31,12 @@ fn main() {
});
handles.push(handle);
}
+
+ // Waiting for all jobs to complete
for handle in handles {
handle.join().unwrap();
- // TODO: Print the value of the JobStatus.jobs_completed. Did you notice
- // anything interesting in the output? Do you have to 'join' on all the
- // handles?
- println!("jobs completed {}", ???);
}
+
+ // TODO: Print the value of `JobStatus.jobs_completed`
+ println!("Jobs completed: {}", ???);
}
diff --git a/info.toml b/info.toml
index b1cd64c..36629b3 100644
--- a/info.toml
+++ b/info.toml
@@ -1136,25 +1136,17 @@ to **immutable** data. But we want to *change* the number of `jobs_completed`
so we'll need to also use another type that will only allow one thread to
mutate the data at a time. Take a look at this section of the book:
https://doc.rust-lang.org/book/ch16-03-shared-state.html#atomic-reference-counting-with-arct
-and keep reading if you'd like more hints :)
-Do you now have an `Arc` `Mutex` `JobStatus` at the beginning of main? Like:
+Keep reading if you'd like more hints :)
+
+Do you now have an `Arc<Mutex<JobStatus>>` at the beginning of `main`? Like:
```
let status = Arc::new(Mutex::new(JobStatus { jobs_completed: 0 }));
```
-Similar to the code in the example in the book that happens after the text
-that says 'Sharing a Mutex<T> Between Multiple Threads'. If not, give that a
-try! If you do and would like more hints, keep reading!!
-
-Make sure neither of your threads are holding onto the lock of the mutex
-while they are sleeping, since this will prevent the other thread from
-being allowed to get the lock. Locks are automatically released when
-they go out of scope.
-
-If you've learned from the sample solutions, I encourage you to come
-back to this exercise and try it again in a few days to reinforce
-what you've learned :)"""
+Similar to the code in the following example in the book:
+https://doc.rust-lang.org/book/ch16-03-shared-state.html#sharing-a-mutext-between-multiple-threads
+"""
[[exercises]]
name = "threads3"