I am trying to understand threading in Python. I’ve looked at the documentation and examples, but quite frankly, many examples are overly sophisticated and I’m having trouble understanding them. How do you clearly show tasks being divided for multi-threading? 2 21 Since this question was asked in 2010, there has been real simplification in how … Read more
Which is the simplest way to update a Label from another Thread? I have a Form running on thread1, and from that I’m starting another thread (thread2). While thread2 is processing some files I would like to update a Label on the Form with the current status of thread2‘s work. How could I do that? … Read more
What is the technical difference between a process and a thread? I get the feeling a word like ‘process’ is overused and there are also hardware and software threads. How about light-weight processes in languages like Erlang? Is there a definitive reason to use one term over the other? 3 37
C++11 introduced a standardized memory model, but what exactly does that mean? And how is it going to affect C++ programming? This article (by Gavin Clarke who quotes Herb Sutter) says that, The memory model means that C++ code now has a standardized library to call regardless of who made the compiler and on what … Read more
From what time I’ve spent with threads in Java, I’ve found these two ways to write threads: With implements Runnable: public class MyRunnable implements Runnable { public void run() { //Code } } //Started with a “new Thread(new MyRunnable()).start()” call Or, with extends Thread: public class MyThread extends Thread { public MyThread() { super(“MyThread”); } … Read more
The whole code is: public class ThreadLocalTest { ThreadLocal<Integer> globalint = new ThreadLocal<Integer>(){ @Override protected Integer initialValue() { return new Integer(0); } }; public class MyThread implements Runnable{ Integer myi; ThreadLocalTest mytest; public MyThread(Integer i, ThreadLocalTest test) { myi = i; mytest = test; } @Override public void run() { System.out.println(“I am thread:” + myi); … Read more
Thread.interrupt() sets the interrupted status/flag of the target thread. Then code running in that target thread MAY poll the interrupted status and handle it appropriately. Some methods that block such as Object.wait() may consume the interrupted status immediately and throw an appropriate exception (usually InterruptedException) Interruption in Java is not pre-emptive. Put another way both threads have to cooperate … Read more
You keep updating both high and low inside the run() method, making them by definition not effectively final. Since you don’t need them outside the run() method anyway, just move the two lines inside. public void HiLo(int[] numbers){ Runnable r2 = new Runnable(){ @Override public void run() { int high = numbers[0]; int low = … Read more
This is wrong: synchronized(foo) { foo.wait(); } The problem is, what’s going to wake this thread up? That is to say, how do you guarantee that the other thread won’t call foo.notify() before the first thread calls foo.wait()? That’s important because the foo object will not remember that it was notified if the notify call … Read more
You need the sleep method of the Thread class. public static void sleep (long time) Causes the thread which sent this message to sleep for the given interval of time (given in milliseconds). The precision is not guaranteed – the Thread may sleep more or less than requested. Parameters time The time to sleep in … Read more
