threads2: simplify threads2

This commit is contained in:
mo8it 2024-03-27 21:24:36 +01:00
parent 58b03af587
commit 842e341895
2 changed files with 13 additions and 18 deletions

View file

@ -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: {}", ???);
}

View file

@ -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"