我希望能够以原子方式递增计数器，但我找不到任何关于如何进行的参考.
根据 comments 添加更多信息:
我想这样做:
class Counter {
private var mux Mutex
private (set) value Int
func increment (){
mux.lock()
value += 1
mux.unlock()
}
}
从Low-Level Concurrency APIs开始:
有一长串的OSAtomicIncrement和OsatomicDecretion
这些函数使用固定大小的整数，您可以 Select
class Counter {
private (set) var value : Int32 = 0
func increment () {
OSAtomicIncrement32(&value)
}
}
(Note:正如埃里克·艾格纳正确地注意到的，OSAtomicIncrement32和
或者，可以使用GCD队列进行同步.
... 使用调度队列，您可以将这两个任务添加到串行队列中
对你来说那就是
// Swift 2:
class Counter {
private var queue = dispatch_queue_create("your.queue.identifier", DISPATCH_QUEUE_SERIAL)
private (set) var value: Int = 0
func increment() {
dispatch_sync(queue) {
value += 1
}
}
}
// Swift 3:
class Counter {
private var queue = DispatchQueue(label: "your.queue.identifier")
private (set) var value: Int = 0
func increment() {
queue.sync {
value += 1
}
}
}
See Adding items to Swift array across multiple threads causing issues (because arrays aren't thread safe) - how do I get around that? or GCD with static functions of a struct for more sophisticated examples. This thread What advantage(s) does dispatch_sync have over @synchronized? is also very interesting.