queue

问题 In this file, the boost::lockfree::detail::freelist class is used to manage storage for a lock-free data structure (e.g., a queue), using a free list. The deallocate_impl method is used to free nodes by linking them back into the free list (a freed node becomes the new head of the free list, displacing the old head). This method is supposed to be thread-safe and lock-free. The original source code of one instance is duplicated here with my comments annotated to point out the suspicious code

问题 I know, queue follow FIFO (First in first out) order, but I am not sure why the following output appears with below java sample program JAVA Sample public static void main(String args[]) { Queue<String> q = new PriorityQueue<String>(); q.add("3"); q.add("1"); q.add("2"); Iterator<String> itr = q.iterator(); while (itr.hasNext()) { System.out.println(itr.next() + " "); } } OUTPUT : 1 3 2 As per Java doc of java.util.PriorityQueue.PriorityQueue() Creates a PriorityQueue with the default initial

问题 UPDATED Having a logic that where a integer before gets enqueued to a queue in a vector, the loop of queues is searched and integer is enqueued to a queue which has minimum size among the queues. The following code shows the operation #include <vector> #include <queue> std::vector<std::queue<int> > q int min_index = 0; std::size_t size = q.size(); for( i=0; i<size; i++){ //accessing loop of queues if(q[min_index].size() > q[i].size()) min_index = i; // Now q[min_index] is the shortest queue }

问题 I want to create a fixed-size thread pool that admits no task into its queue. In other words, if the thread pool is currently in use, the incoming task should be rejected outright. Based on the documentation, one way to do this, in my opinion, would be to create a dummy Queue object which refuses to admit a task. What is the idiomatic way to accomplish this in Java? 回答1: You can use a SynchronousQueue in your ThreadPoolExector which is a queue which holds no objects. The cached thread pool

问题 First of all, just grant that I do in fact want the functionality of a Queue<T> -- FIFO, generally only need Enqueue / Dequeue , etc. -- and so I'd prefer an answer other than "What you really want is a List<T> " (I know about RemoveAt ). For example, say I have a Queue<DataPoint> dataToProcess of data points that need to be processed in the order in which they arrived. Then periodically it would make sense to have some code like this: while (dataToProcess.Count > 0) { DataPoint

问题 I try to add progress bar on my application. I found the question on How to add Progress bar to UIAlertController? but it didn't show how to update the progress bar. I simplify the code as below but it didn't update the progress bar (it shows only once the progress is completed). What did i over look? Thank you for your help. override func viewDidLoad() { super.viewDidLoad() var topViewController = UIApplication.shared.delegate!.window!!.rootViewController! while (topViewController

问题 I'm trying to translate the following JS code to ObjC; It basically defines a function and store it in an array for later execution: var logic = function() { me.removeNode(node); } this.queue.push(logic); My ObjC port contains the method: -(void)removeNode:(AbstractNode*)node and I'm stuck... I would like to just queue a call to this method using the specified "node" argument... edit: I'm reading about selectors. It's still blurry, but might help. Somehow. Or not? Is it even possible, or will

问题 I've seen this way of implementing a queue with two stacks: https://stackoverflow.com/a/2050402/494094 And I've read that this way the queue is immutable and thread-safe. What's the point that separates this from a normal queue and makes it immutable and thread-safe? I'd really appreciate it if someone could explain it in a simple, non-professional way. 回答1: How to implement a queue using two stacks? explains more and has some code. If you do this in a low-level way you will have two memory

问题 I'm creating an iOS app by swift that is as same as the AliExpress iOS app. This App has ability that connect to our site and download all of data from JSON api online. Now, I wanna download the images of the icons and banner slider from our site by JSON api in main page. But I don't know how i can do it. Do I use queues or background functions like in android? Also, I'm an android developer and i know how i can do this in android. You can guide me by this way ,too. please guide me by sample

问题 I created a script to monitor a set of queues, and, while it works perfectly with Remote Private Queues, it doesn't work with Outgoing Queues. I made an experiment by removing everything but the essential from the script, and I created the following test script: var info = new ActiveXObject("MSMQ.MSMQQueueInfo"); info.FormatName = /*<Queue name>*/; // 0x80 = MQ_ADMIN_ACCESS // 0x20 = MQ_PEEK_ACCESS // 0x00 = MQ_DENY NONE var mq = info.Open(0x80 | 0x20, 0x00); var msg = mq.PeekCurrent(false,