blob: bc268d63f64a29ca53644077074a3533b63285af (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
|
// Building on the last exercise, we want all of the threads to complete their
// work. But this time, the spawned threads need to be in charge of updating a
// shared value: `JobStatus.jobs_done`
use std::{
sync::{Arc, Mutex},
thread,
time::Duration,
};
struct JobStatus {
jobs_done: u32,
}
fn main() {
// `Arc` isn't enough if you want a **mutable** shared state.
// We need to wrap the value with a `Mutex`.
let status = Arc::new(Mutex::new(JobStatus { jobs_done: 0 }));
// ^^^^^^^^^^^ ^
let mut handles = Vec::new();
for _ in 0..10 {
let status_shared = Arc::clone(&status);
let handle = thread::spawn(move || {
thread::sleep(Duration::from_millis(250));
// Lock before you update a shared value.
status_shared.lock().unwrap().jobs_done += 1;
// ^^^^^^^^^^^^^^^^
});
handles.push(handle);
}
// Waiting for all jobs to complete.
for handle in handles {
handle.join().unwrap();
}
println!("Jobs done: {}", status.lock().unwrap().jobs_done);
// ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
}
|
