multithreading

问题 I thought the point of a multi-core computer is that it could run multiple threads simultaneously. In that case, if you have a quad-core machine, what's the point of having more than 4 threads running at a time? Wouldn't they just be stealing time from each other? 回答1: The answer revolves around the purpose of threads, which is parallelism: to run several separate lines of execution at once. In an 'ideal' system, you would have one thread executing per core: no interruption. In reality this

问题 How do you start a thread with parameters in C#? 回答1: Yep : Thread t = new Thread (new ParameterizedThreadStart(myMethod)); t.Start (myParameterObject); 回答2: One of the 2 overloads of the Thread constructor takse a ParameterizedThreadStart delegate which allows you to pass a single parameter to the start method. Unfortunately though it only allows for a single parameter and it does so in an unsafe way because it passes it as object. I find it's much easier to use a lambda expression to

问题 I am having trouble using the WPF Extended Toolkit (version 2.1.0.0) MessageBox from other threads. The namespace is: Xceed.Wpf.Toolkit.MessageBox I replaced my regular MessageBoxs (System.Windows.MessageBox) with the Toolkit MessageBox and get errors when I launch one from another thread. The System.Windows.MessageBox has no such problems. I saw this posting that reports the problem, but there seems to be no follow up: https://wpftoolkit.codeplex.com/workitem/21046 I'm guessing there is a

问题 I am having trouble using the WPF Extended Toolkit (version 2.1.0.0) MessageBox from other threads. The namespace is: Xceed.Wpf.Toolkit.MessageBox I replaced my regular MessageBoxs (System.Windows.MessageBox) with the Toolkit MessageBox and get errors when I launch one from another thread. The System.Windows.MessageBox has no such problems. I saw this posting that reports the problem, but there seems to be no follow up: https://wpftoolkit.codeplex.com/workitem/21046 I'm guessing there is a

问题 I got very confused by reading Thread Pooling. I learnt the concept, how they actually works. But I confused in the part , how to code this. I searched a lot on the net. Finally I got a blog, that have codes , given below, CONDITION IS, NOT TO USE IN-BUILT CLASS Code 1 public class ThreadPool { private BlockingQueue taskQueue = null; private List<PoolThread> threads = new ArrayList<PoolThread>(); private boolean isStopped = false; public ThreadPool(int noOfThreads, int maxNoOfTasks){

问题 I'm making a .bat dynamically in Java . After creating the file and exectuing it, I want to delete it. In order to make sure that delete() will be executing after running the .bat file, I delete the file within a different thread. Is this a good approach for this task? How would you implement it in a better way? final File file = new File("run.bat"); file.createNewFile(); PrintWriter writer = new PrintWriter(file, "UTF-8"); writer.println(COMMAND1); writer.println(COMMAND2); .... ANOTHER

问题 This question already has answers here : What is a NullPointerException, and how do I fix it? (12 answers) Closed 2 years ago . I am creating a multi-threaded web server. When I run the client I receive a NullPointException. Why is this happening and what can be done to solve it? Concerning the suggestions that I should read the mentioned tutorial. I have tried to solve the problem with the help of it. I created a constructor, but then I didn't know how to call the class: theExecutor.execute

问题 Scenario: I have written a big piece of code, running on 2 parallel threads, which are identical in term of code and just process different data. I am seeing non-deterministic results. If I disable one of the 2 threads, the results become deterministic. Within this code I am using some static inline functions (main reason: they are small functions that I need here and there, for which I simply duplicate the code in the translation units where they are needed), and I would like to understand

问题 How can I make use of Semaphore class in order to control number of threads that have an access to an object? 回答1: Initialize the Semaphore with the max number of alowed threds, reduce the semaphore counter by one if a thread enters the restricted area increse the semaphore counter by one if the thred leaves the restricted area 回答2: One more good thing about using semaphore to control access to resouce is you can resize your semaphore at runtime. For eg you can have some use case where you

问题 in my android application I want to send requests to server via sms if there was no internet connection or network. I am changing the Volley library code. http request is synchronous, when you send the request, thread waits until the response or error get received from server, but when you send sms, thread continue to work and doesn't wait to get the response sms so I am forced to use Callback functions(listeners). is there any better approach. is it good idea to use wait and notify to make