在Rust中,loop能够对循环体添加命名标签,经常用于多个循环存在,而只想用break退出其中一个的情形,看下代码。 // loop_labels.rs fn silly_sub(a: i32, b: i32) -> i32 { let mut result = 0; 'increment: loop { if result == a { let mut dec = b; 'decrement: loop { if dec == 0 { /...
// loop_labels.rs fn silly_sub(a: i32, b: i32) -> i32 { let mut result = 0; 'increment: loop { if result == a { let mut dec = b; 'decrement: loop { if dec == 0 { //直接从 'increment循环中断 break 'increment; } else { result -= 1; dec -= 1; } } } else { ...
counter.update(Message::Increment);counter.update(Message::Increment);counter.update(Message::Decrement); 这将使我们的计数器最终的值为 1: assert_eq!(counter.value,1); 实际上,我们刚刚为我们的应用程序逻辑编写了一个简单的测试: #[test]fnit_counts_properly(){letmutcounter=Counter{value:0};counter...
Rust for loops call into_iter() (defined on the IntoIterator trait) for whatever they're iterating over. Anything implementing the IntoIterator trait may be looped over with a for loop. IntoIterator is implemented for &Vec and &mut Vec, causing the iterator from into_iter() to borrow the...
impl<R,T>DropforJoinHandle<R,T>{fndrop(&mut self){letptr=self.raw_task.as_ptr();letheader=ptras*constHeader;letmut output=None;unsafe{// 由于很多时候JoinHandle不用,会在刚创建的时候直接drop掉,因此针对这种情// 况作一个特殊化处理。这样一个原子操作就完成了。ifletErr(mut state)=(*header...
for sure looks like it assumes that a panicking next_back call will always at least decrement the size.But – funnily enough – the very same code section lives in a next_back impl – at the beginning of that impl – being code that can panick but up to this point nothing happened tha...
std::thread::spawn(move|| loop{ std::thread::sleep(std::time::Duration::from_secs(2));fordeadlockinparking_lot::deadlock::check_deadlock() {fordeadlockindeadlock {println!("Found a deadlock!{}:\n{:?}", deadlock.thread_id(), ...
The print thing is just an example to say we can print the data. The drop method… In Rust the structures are called, drop. The drop method will do a fetch-and-decrement on the count field, and if it sees that it’s the last one out the door, it will deallocate the object. Okay...
= 0 { // poll的时候其他线程想schedule这个task,但是不能调用,因此 // 当前线程代劳。chedule函数接收self,类似move语义,因此这里 // 不需要decrement。 Self::schedule(ptr); } else { Self::decrement(ptr); } break; } Err(s) => state = s, } } }}...
fn decrement_num_running_threads(&self, panic: bool) { if panic { self.a_thread_panicked.store(true, Ordering::Relaxed); } //减少线程计数 if self.num_running_threads.fetch_sub(1, Ordering::Release) == 1 { //唤醒主线程 self.main_thread.unpark(); } } } ...