fix(threads1): make program panic if threads are not joined

closes #1298
This commit is contained in:
platformer 2022-12-26 02:25:43 -06:00
parent 32b234c9f0
commit 7e4ce38681
2 changed files with 17 additions and 10 deletions

View File

@ -1,31 +1,38 @@
// threads1.rs
// Execute `rustlings hint threads1` or use the `hint` watch subcommand for a hint.
// This program should wait until all the spawned threads have finished before exiting.
// This program spawns multiple threads that each run for at least 250ms,
// and each thread returns how much time they took to complete.
// The program should wait until all the spawned threads have finished and
// should collect their return values into a vector.
// I AM NOT DONE
use std::thread;
use std::time::Duration;
use std::time::{Duration, Instant};
fn main() {
let mut handles = vec![];
for i in 0..10 {
thread::spawn(move || {
handles.push(thread::spawn(move || {
let start = Instant::now();
thread::sleep(Duration::from_millis(250));
println!("thread {} is complete", i);
});
start.elapsed().as_millis()
}));
}
let mut completed_threads = 0;
let mut results: Vec<u128> = vec![];
for handle in handles {
// TODO: a struct is returned from thread::spawn, can you use it?
completed_threads += 1;
}
if completed_threads != 10 {
if results.len() != 10 {
panic!("Oh no! All the spawned threads did not finish!");
}
println!();
for (i, result) in results.into_iter().enumerate() {
println!("thread {} took {}ms", i, result);
}
}

View File

@ -969,7 +969,7 @@ A challenge with multi-threaded applications is that the main thread can
finish before the spawned threads are completed.
https://doc.rust-lang.org/book/ch16-01-threads.html#waiting-for-all-threads-to-finish-using-join-handles
Collect the JoinHandles and wait for them to finish.
Use the JoinHandles to wait for each thread to finish and collect their results.
https://doc.rust-lang.org/std/thread/struct.JoinHandle.html
"""