Hi !
Let’s take a look at the following code.
- The main thread will run a loop for ~5 seconds, displaying a message every 1 second.
- The 2nd thread with display a message, wait 5 seconds and display a 2nd message.
/* | |
Copyright (c) 2023 | |
Author : Bruno Capuano | |
Create Time : 2023 January | |
Change Log : | |
- Demos working with threads in Rust | |
The MIT License (MIT) | |
Permission is hereby granted, free of charge, to any person obtaining a copy | |
of this software and associated documentation files (the "Software"), to deal | |
in the Software without restriction, including without limitation the rights | |
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell | |
copies of the Software, and to permit persons to whom the Software is | |
furnished to do so, subject to the following conditions: | |
The above copyright notice and this permission notice shall be included in | |
all copies or substantial portions of the Software. | |
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR | |
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, | |
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE | |
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER | |
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, | |
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN | |
THE SOFTWARE. | |
*/ | |
use std::thread; | |
use std::time::Duration; | |
fn main() { | |
thread::spawn(|| { | |
println!(" >> Begin thread work, wait 5 seconds ..."); | |
thread::sleep(Duration::from_millis(5000)); | |
println!(" >> End thread work ..."); | |
}); | |
for i in 0..5 { | |
println!("Loop 1 iteration: {}", i); | |
thread::sleep(Duration::from_millis(500)); | |
} | |
} |
The code output shows that the app is closed before finishing the execution of the 2nd thread.
Joining thread handles
When we work in multi-threading scenarios, the previous problem is solved joining threads (joining thread handles). We need to join the 2nd thread and the main thread.
In order to do this, we just assign the 2nd thread to a variable.
let sec_thread = thread::spawn(|| { ...
And to join the handles we use the .join().unwrap() method.
Note: unwrap() will help us handle possible errors.
The full code looks like this.
/* | |
Copyright (c) 2023 | |
Author : Bruno Capuano | |
Create Time : 2023 January | |
Change Log : | |
- Demos working with threads in Rust | |
The MIT License (MIT) | |
Permission is hereby granted, free of charge, to any person obtaining a copy | |
of this software and associated documentation files (the "Software"), to deal | |
in the Software without restriction, including without limitation the rights | |
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell | |
copies of the Software, and to permit persons to whom the Software is | |
furnished to do so, subject to the following conditions: | |
The above copyright notice and this permission notice shall be included in | |
all copies or substantial portions of the Software. | |
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR | |
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, | |
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE | |
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER | |
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, | |
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN | |
THE SOFTWARE. | |
*/ | |
use std::thread; | |
use std::time::Duration; | |
fn main() { | |
let sec_thread = thread::spawn(|| { | |
println!(" >> Begin thread work, wait 5 seconds ..."); | |
thread::sleep(Duration::from_millis(5000)); | |
println!(" >> End thread work ..."); | |
}); | |
for i in 0..5 { | |
println!("Loop 1 iteration: {}", i); | |
thread::sleep(Duration::from_millis(500)); | |
} | |
sec_thread.join().unwrap(); | |
} |
And we have the expected output.
In next posts, more about threads in Rust.
Happy coding!
Greetings
El Bruno
More posts in my blog ElBruno.com.
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