頭條地址:https://www.ixigua.com/i677586170644791348...
B站地址:https://www.bilibili.com/video/av81202308/
github地址:https://github.com/anonymousGiga/learn_rus...
1、執行緒間共享Mutex
(1)錯誤例子:
use std::sync::Mutex;
use std::thread;
fn main() {
let counter = Mutex::new(0);
let mut handles = vec![];
for _ in 0..10 {
let handle = thread::spawn(move || {
let mut num = counter.lock().unwrap();
*num += 1;
});
handles.push(handle);
}
for handle in handles {
handle.join().unwrap();
}
println!("Result: {}", *counter.lock().unwrap());
}
錯誤原因:不能將counter鎖的所有權移動到多個執行緒中。
(2)錯誤例子2:透過Rc來建立引用計數的值
use std::rc::Rc;
use std::sync::Mutex;
use std::thread;
fn main() {
let counter = Rc::new(Mutex::new(0));
let mut handles = vec![];
for _ in 0..10 {
let counter = Rc::clone(&counter);
let handle = thread::spawn(move || {
let mut num = counter.lock().unwrap();
*num += 1;
});
handles.push(handle);
}
for handle in handles {
handle.join().unwrap();
}
println!("Result: {}", *counter.lock().unwrap());
}
錯誤原因:Rc不是執行緒安全的
(3)例子3:使用Arc
說明: Arc是一個類似於Rc並可以安全的用於併發環境的型別,程式碼如下:
use std::sync::{Mutex, Arc};
use std::thread;
fn main() {
let counter = Arc::new(Mutex::new(0));
let mut handles = vec![];
for _ in 0..10 {
let counter = Arc::clone(&counter);
let handle = thread::spawn(move || {
let mut num = counter.lock().unwrap();
*num += 1;
});
handles.push(handle);
}
for handle in handles {
handle.join().unwrap();
}
println!("Result: {}", *counter.lock().unwrap());
}
2、RefCell/Rc 與 Mutex/Arc 的相似性
(1)Mutex提供內部可變性,類似於RefCell;
(2)RefCell/Rc是非執行緒安全的,而Mutex/Arc是執行緒安全的。
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