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  • Error with `Thread.Sleep` during automatic testing on TeamCity 5

    - by yeyeyerman
    Hello, I'm having some problems executing the tests of the application I'm developing. All the tests execute normally with ReSharper and in NCover. However, the execution of one of these tests in TeamCity is generating an error. This test initializes two objects, the object under test and a simulator of a real object. Both objects will communicate throug a serial link in a representation of the real scenario. ObjectSimulator r_simulator = new ObjectSimulator(...); ObjectDriver r_driver = new ObjectDriver(...); Assert.IsTrue(r_driver.Connect() == ErrorCode.Success); The simulator just do the following in the constructor public class ObjectSimulator { ... public ObjectSimulator() { // serial port configuration m_port = new SerialPort(); m_port.DataReceived += DataReceivedEvent; } ... } The main object has two threads. The main thread of the application and a timer to refresh a watchdog timer in the real object. public ErrorCode Connect() { ... StartSynchroTimer(); Thread.Sleep(4); // to check if the timer is working properly ... } The problem seems to be comming from the Thread.Sleep() call, as when I remove it everything works. The ObjectSimulator somehow doesn't execute the DataReceived event callback. How can I resolve this issue?

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  • How to use CriticalSection - MFC?

    - by mapples
    I' am working on a small example and am a bit of curious using criticalsection in my example. What I'am doing is,I have a CStringArray(which has 10 elements added to it).I want to copy these 10 elements(string) to another CStringArray(am doing this to understand threading and Critical section),I have created 2 threads,Thread1 will copy the first 5 element to another CStringArray and Thread2 will copy the rest.Here two CStringArray are being used,I know only 1 thread can access it at a time.I wanted to know how this can be solved by using criticalsection or any other method. void CThreadingEx4Dlg::OnBnClickedOk() { // TODO: Add your control notification handler code here thread1 = AfxBeginThread((AFX_THREADPROC)MyThreadFunction1,this); thread2 = AfxBeginThread((AFX_THREADPROC)MyThreadFunction2,this); } UINT MyThreadFunction1(LPARAM lparam) { CThreadingEx4Dlg* pthis = (CThreadingEx4Dlg*)lparam; pthis->MyFunction(0,5); return 0; } UINT MyThreadFunction2(LPARAM lparam) { CThreadingEx4Dlg* pthis = (CThreadingEx4Dlg*)lparam; pthis->MyFunction(6,10); return 0; } void CThreadingEx4Dlg::MyFunction(int minCount,int maxCount) { for(int i=minCount;i<=maxCount;i++) { CString temp; temp = myArray.GetAt(i); myShiftArray.Add(temp); } }

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  • How do I make child thread exit when main thread exit?

    - by httpinterpret
    void forloop2() { int i = 0; while(TRUE) { printf("forloop2\n"); } } int main() { GThread *Thread1; GtkWidget *window; g_thread_init(NULL); gdk_threads_init(); gdk_threads_enter (); Thread1 = g_thread_create((GThreadFunc)forloop2, NULL, TRUE, NULL); gtk_init(NULL, NULL); window = gtk_window_new(GTK_WINDOW_TOPLEVEL); gtk_widget_show_all (window); gtk_main(); g_thread_join(Thread1); gdk_threads_leave (); } When I close the window, how to make Thread1 also exit?

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  • Can two or more threads iterate over the same List<t> without any problems?

    - by CodingCrapper
    Talking about System.Collections.Generic.List here. With example below can Method1 and Method2 execute and the same time, on different threads without any problems? Thanks class Test { private readonly List<MyData> _data; public Test() { _data = LoadData(); } private List<MyData> LoadData() { //Get data from dv. } public void Method1() { foreach (var list in _data) { //do something } } public void Method2() { foreach (var list in _data) { //do something } } }

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  • ThreadQueue problems in "Accelerated C# 2008"

    - by Singlet
    Example for threading queue book "Accelerated C# 2008" (CrudeThreadPool class) not work correctly. If I insert long job in WorkFunction() on 2-processor machine executing for next task don't run before first is over. How to solve this problem? I want to load the processor to 100 percent public class CrudeThreadPool { static readonly int MAX_WORK_THREADS = 4; static readonly int WAIT_TIMEOUT = 2000; public delegate void WorkDelegate(); public CrudeThreadPool() { stop = 0; workLock = new Object(); workQueue = new Queue(); threads = new Thread[ MAX_WORK_THREADS ]; for( int i = 0; i < MAX_WORK_THREADS; ++i ) { threads[i] = new Thread( new ThreadStart(this.ThreadFunc) ); threads[i].Start(); } } private void ThreadFunc() { lock( workLock ) { int shouldStop = 0; do { shouldStop = Interlocked.Exchange( ref stop, stop ); if( shouldStop == 0 ) { WorkDelegate workItem = null; if( Monitor.Wait(workLock, WAIT_TIMEOUT) ) { // Process the item on the front of the queue lock( workQueue ) { workItem =(WorkDelegate) workQueue.Dequeue(); } workItem(); } } } while( shouldStop == 0 ); } } public void SubmitWorkItem( WorkDelegate item ) { lock( workLock ) { lock( workQueue ) { workQueue.Enqueue( item ); } Monitor.Pulse( workLock ); } } public void Shutdown() { Interlocked.Exchange( ref stop, 1 ); } private Queue workQueue; private Object workLock; private Thread[] threads; private int stop; } public class EntryPoint { static void WorkFunction() { Console.WriteLine( "WorkFunction() called on Thread {0}",Thread.CurrentThread.GetHashCode() ); //some long job double s = 0; for (int i = 0; i < 100000000; i++) s += Math.Sin(i); } static void Main() { CrudeThreadPool pool = new CrudeThreadPool(); for( int i = 0; i < 10; ++i ) { pool.SubmitWorkItem( new CrudeThreadPool.WorkDelegate( EntryPoint.WorkFunction) ); } pool.Shutdown(); } }

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  • Multithreaded Applications

    - by j-t-s
    Hi All I have been reading the articles on MSDN, but my mind is dead (this usually happens when I read MSDN (No offense MSDN, but your articles confuse me at times.)), and I'm trying to do some "background work" in may app, but not sure how. It's just a single method. But the application hangs, and I have to wait up to 1 - 3 minutes for it to become ...unhanged? Are there any simple examples that are laying 'roun online somewhere that I can have a look at/play around with? Thank you all

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  • How to tell if there is an available thread in a thread pool in java

    - by Gormcito
    I am trying to proccess a queue of tasks from a database table as fast as possible while also limiting the number of threads to process the tasks. I am using a fixed sized thread pool with Executors.newFixedThreadPool(N); I want to know if there is a way of knowing if the thread pool is full, by that I mean are there currently 50 threads running, if so then I'll wait for a thread to be available before starting a new one instead of sleeping the main thread. Code of what I would like to do: ExecutorService executor = Executors.newFixedThreadPool(N); ResultSet results; while( true ) { results = getWaitingTasksStmt.executeQuery(); while( results.next() && executor.notFull() ) { executor.submit( new thread( new runnableInheritedClass(results) ) ); } }

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  • c# run process without freezing my App's GUI

    - by Data-Base
    Hello, I want to start a process (calling another program), currently the external program takes time (it is normal)! but it freezes my GUI I saw allot of examples and I'm learning, it is hard to figure it out, trying to read and learn threading, but it is not that easy (at least for me) and good simple tutorial or code sample? cheers

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  • Queues And Wait Handles in C#

    - by Michael Covelli
    I've had the following code in my application for some years and have never seen an issue from it. while ((PendingOrders.Count > 0) || (WaitHandle.WaitAny(CommandEventArr) != 1)) { lock (PendingOrders) { if (PendingOrders.Count > 0) { fbo = PendingOrders.Dequeue(); } else { fbo = null; } } // Do Some Work if fbo is != null } Where CommandEventArr is made up of the NewOrderEvent (an auto reset event) and the ExitEvent (a manual reset event). But I just realized today that its not thread safe at all. If this thread gets interrupted right after the first (PendingOrder.Count 0) check has returned false. And then the other thread both enqueues an order and sets the NewOrderEvent before I get a chance to wait on it, the body of the while loop will never run. What's the usual pattern used with a Queue and an AutoResetEvent to fix this and do what I'm trying to do with the code above?

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  • [C++] Start a thread using a method pointer

    - by Michael
    Hi ! I'm trying to develop a thread abstraction (POSIX thread and thread from the Windows API), and I would very much like it to be able to start them with a method pointer, and not a function pointer. What I would like to do is an abstraction of thread being a class with a pure virtual method "runThread", which would be implanted in the future threaded class. I don't know yet about the Windows thread, but to start a POSIX thread, you need a function pointer, and not a method pointer. And I can't manage to find a way to associate a method with an instance so it could work as a function. I probably just can't find the keywords (and I've been searching a lot), I think it's pretty much what Boost::Bind() does, so it must exist. Can you help me ?

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  • Waiting for thread to finish Python

    - by lunchtime
    Alright, here's my problem. I have a thread that creates another thread in a pool, applies async so I can work with the returned data, which is working GREAT. But I need the current thread to WAIT until the result is returned. Here is the simplified code, as the current script is over 300 lines. I'm sure i've included everything for you to make sense of what I'm attempting: from multiprocessing.pool import ThreadPool import threading pool = ThreadPool(processes=1) class MyStreamer(TwythonStreamer): #[...] def on_success(self, data): #### Everytime data comes in, this is called #[...] #<Pseudocode> if score >= limit if list exists: Do stuff elif list does not exist: #</Pseudocode> dic = [] dic.append([k1, v1]) did = dict(dic) async_result = pool.apply_async(self.list_step, args=(did)) return_val = async_result.get() slug = return_val[0] idd = return_val[1] #[...] def list_step(self, *args): ## CREATE LIST ## RETURN 2 VALUES class threadStream (threading.Thread): def __init__(self, auth): threading.Thread.__init__(self) self.auth = auth def run(self): stream = MyStreamer(auth = auth[0], *auth[0]) stream.statuses.filter(track=auth[1]) t = threadStream(auth=AuthMe) t.start() I receive the results as intended, which is great, but how do I make it so this thread t waits for the async_result to come in?? My problem is everytime new data comes in, it seems that the ## CREATE LIST function is called multiple times if similar data comes in quickly enough. So I'm ending up with many lists of the same name when I have code in place to ensure that a list will never be created if the name already exists. So to reiterate: How do I make this thread wait on the function to complete before accepting new data / continuing. I don't think time.sleep() works because on_success is called when data enters the stream. I don't think Thread.Join() will work either since I have to use a ThreadPool.apply_async to receive the data I need. Is there a hack I can make in the MyStreamer class somehow? I'm kind of at a loss here. Am I over complicating things and can this be simplified to do what I want?

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  • java threads don't see shared boolean changes

    - by andymur
    Here the code class Aux implements Runnable { private Boolean isOn = false; private String statusMessage; private final Object lock; public Aux(String message, Object lock) { this.lock = lock; this.statusMessage = message; } @Override public void run() { for (;;) { synchronized (lock) { if (isOn && "left".equals(this.statusMessage)) { isOn = false; System.out.println(statusMessage); } else if (!isOn && "right".equals(this.statusMessage)) { isOn = true; System.out.println(statusMessage); } if ("left".equals(this.statusMessage)) { System.out.println("left " + isOn); } } } } } public class Question { public static void main(String [] args) { Object lock = new Object(); new Thread(new Aux("left", lock)).start(); new Thread(new Aux("right", lock)).start(); } } In this code I expect to see: left, right, left right and so on, but when Thread with "left" message changes isOn to false, Thread with "right" message don't see it and I get ("right true" and "left false" console messages), left thread don't get isOn in true, but right Thread can't change it cause it always see old isOn value (true). When i add volatile modifier to isOn nothing changes, but if I change isOn to some class with boolean field and change this field then threads are see changes and it works fine Thanks in advance.

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  • Updating table from async task android

    - by CantChooseUsernames
    I'm following this tutorial: http://huuah.com/android-progress-bar-and-thread-updating/ to learn how to make progress bars. I'm trying to show the progress bar on top of my activity and have it update the activity's table view in the background. So I created an async task for the dialog that takes a callback: package com.lib.bookworm; import android.app.ProgressDialog; import android.content.Context; import android.os.AsyncTask; public class UIThreadProgress extends AsyncTask<Void, Void, Void> { private UIThreadCallback callback = null; private ProgressDialog dialog = null; private int maxValue = 100, incAmount = 1; private Context context = null; public UIThreadProgress(Context context, UIThreadCallback callback) { this.context = context; this.callback = callback; } @Override protected Void doInBackground(Void... args) { while(this.callback.condition()) { this.callback.run(); this.publishProgress(); } return null; } @Override protected void onProgressUpdate(Void... values) { super.onProgressUpdate(values); dialog.incrementProgressBy(incAmount); }; @Override protected void onPreExecute() { super.onPreExecute(); dialog = new ProgressDialog(context); dialog.setCancelable(true); dialog.setMessage("Loading..."); dialog.setProgress(0); dialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL); dialog.setMax(maxValue); dialog.show(); } @Override protected void onPostExecute(Void result) { super.onPostExecute(result); if (this.dialog.isShowing()) { this.dialog.dismiss(); } this.callback.onThreadFinish(); } } And in my activity, I do: final String page = htmlPage.substring(start, end).trim(); //Create new instance of the AsyncTask.. new UIThreadProgress(this, new UIThreadCallback() { @Override public void run() { row_id = makeTableRow(row_id, layout, params, matcher); //ADD a row to the table layout. } @Override public void onThreadFinish() { System.out.println("FINISHED!!"); } @Override public boolean condition() { return matcher.find(); } }).execute(); So the above creates an async task to run to update a table layout activity while showing the progress bar that displays how much work has been done.. However, I get an error saying that only the thread that started the activity can update its views. I tried doing: MainActivity.this.runOnUiThread(new Runnable() { @Override public void run() { row_id = makeTableRow(row_id, layout, params, matcher); //ADD a row to the table layout. } } But this gives me synchronization errors.. Any ideas how I can display progress and at the same time update my table in the background? Currently my UI looks like:

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  • The cross-thread usage of "HttpContext.Current" property and related things

    - by smwikipedia
    I read from < Essential ASP.NET with Examples in C# the following statement: Another useful property to know about is the static Current property of the HttpContext class. This property always points to the current instance of the HttpContext class for the request being serviced. This can be convenient if you are writing helper classes that will be used from pages or other pipeline classes and may need to access the context for whatever reason. By using the static Current property to retrieve the context, you can avoid passing a reference to it to helper classes. For example, the class shown in Listing 4-1 uses the Current property of the context to access the QueryString and print something to the current response buffer. Note that for this static property to be correctly initialized, the caller must be executing on the original request thread, so if you have spawned additional threads to perform work during a request, you must take care to provide access to the context class yourself. I am wondering about the root cause of the bold part, and one thing leads to another, here is my thoughts: We know that a process can have multiple threads. Each of these threads have their own stacks, respectively. These threads also have access to a shared memory area, the heap. The stack then, as I understand it, is kind of where all the context for that thread is stored. For a thread to access something in the heap it must use a pointer, and the pointer is stored on its stack. So when we make some cross-thread calls, we must make sure that all the necessary context info is passed from the caller thread's stack to the callee thread's stack. But I am not quite sure if I made any mistake. Any comments will be deeply appreciated. Thanks. ADD Here the stack is limited to user stack.

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  • Multi threading question..

    - by dotnet-practitioner
    I would like to invoke heavy duty method dowork on a separate thread and kill it if its taking longer than 3 seconds. Is there any problem with the following code? class Class1 { /// <summary> /// The main entry point for the application. /// </summary> [STAThread] static void Main(string[] args) { Console.WriteLine("starting new thread"); Thread t = new Thread(new ThreadStart(dowork)); t.Start(); DateTime start = DateTime.Now; TimeSpan span = DateTime.Now.Subtract(start); bool wait = true; while (wait == true) { if (span.Seconds > 3) { t.Abort(); wait = false; } span = DateTime.Now.Subtract(start); } Console.WriteLine("ending new thread after seconds = {0}", span.Seconds); Console.WriteLine("all done"); Console.ReadLine(); } static void dowork() { Console.WriteLine("doing heavy work inside hello"); Thread.Sleep(7000); Console.WriteLine("*** finished**** doing heavy work inside hello"); } }

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  • Java synchronizing static list ?

    - by JavaUser
    Hi, In a Java class , i am having a static list so this list is shared across all the objects of this class.The business logic in this class will run periodically which is invoked by some method with out passing instance parameters.Now I want to invoke this run method based on the list(I will add some vales into this list based on JMS) ,this list may empty sometimes and after finishing the run , i am emptying this list.Now my question is , whether I need to synchronize this list or not? Also let me know is there any other way to pass value in one object instance(Thread1) to other object instance (Thread2) other than having Static variable(static list)? Thx

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  • Timer C#. Start, stop, and get the amount of time between the calls

    - by user1886060
    I'm writing UDP chat with reliable data transfer. I need to start a timer when a packet is sent, and stop it as soon it receives an answer from the server(ACK- acknowledgment). Here is my code: private void sendButton_Click(object sender, EventArgs e) { Packet snd = new Packet(ack, textBox1.Text.Trim()); textBox1.Text = string.Empty; Smsg = snd.GetDataStream();//convert message into array of bytes to send. while (true) { try { // Here I need to Start a timer! clientSock.SendTo(Smsg, servEP); clientSock.ReceiveFrom(Rmsg, ref servEP); //Here I need to stop a timer and get elapsed amount of time. Packet rcv = new Packet(Rmsg); if (Rmsg != null && rcv.ACK01 != ack) continue; if (Rmsg != null && rcv.ACK01 == ack) { this.displayMessageDelegate("ack is received :"+ack); ChangeAck(ack); break; } Thank you.

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  • Thread-safe get (accessor method)

    - by sonofdelphi
    I'm currently using the following code for thread-safe access of a variable. int gnVariable; void getVariableValue(int *pnValue) { acquireLock(); //Acquires the protection mechanism *pnValue = gnVariable; releaseLock(); //Releasing the protection mechanism } I would like to change my API signature to a more user-friendly int getVariableValue(void); How should I rewrite the function - such that the users of the API don't have to bother about the locking/unlocking details?

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  • Waiting on threads

    - by Paul Reiners
    I have a method that contains the following (Java) code: doSomeThings(); doSomeOtherThings(); doSomeThings() creates some threads, each of which will run for only a finite amount of time. The problem is that I don't want doSomeOtherThings() to be called until all the threads launched by doSomeThings() are finished. (Also doSomeThings() will call methods that may launch new threads and so on. I don't want to execute doSomeOtherThings() until all these threads have finished.) This is because doSomeThings(), among other things will set myObject to null, while doSomeOtherThings() calls myObject.myMethod() and I do not want myObject to be null at that time. Is there some standard way of doing this kind of thing (in Java)?

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  • Help with java threads or executors: Executing several MySQL selects, inserts and updates simmultane

    - by Martin
    Hi. I'm writing an application to analyse a MySQL database, and I need to execute several DMLs simmultaneously; for example: // In ResultSet rsA: Select * from A; rsA.beforeFirst(); while (rsA.next()) { id = rsA.getInt("id"); // Retrieve data from table B: Select * from B where B.Id=" + id; // Crunch some numbers using the data from B // Close resultset B } I'm declaring an array of data objects, each with its own Connection to the database, which in turn calls several methods for the data analysis. The problem is all threads use the same connection, thus all tasks throw exceptios: "Lock wait timeout exceeded; try restarting transaction" I believe there is a way to write the code in such a way that any given object has its own connection and executes the required tasks independent from any other object. For example: DataObject dataObject[0] = new DataObject(id[0]); DataObject dataObject[1] = new DataObject(id[1]); DataObject dataObject[2] = new DataObject(id[2]); ... DataObject dataObject[N] = new DataObject(id[N]); // The 'DataObject' class has its own connection to the database, // so each instance of the object should use its own connection. // It also has a "run" method, which contains all the tasks required. Executor ex = Executors.newFixedThreadPool(10); for(i=0;i<=N;i++) { ex.execute(dataObject[i]); } // Here where the problem is: Each instance creates a new connection, // but every DML from any of the objects is cluttered in just one connection // (in MySQL command line, "SHOW PROCESSLIST;" throws every connection, and all but // one are idle). Can you point me in the right direction? Thanks

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  • Is it thread safe to read a form controls value (but not change it) without using Invoke/BeginInvoke from another thread

    - by goku_da_master
    I know you can read a gui control from a worker thread without using Invoke/BeginInvoke because my app is doing it now. The cross thread exception error is not being thrown and my System.Timers.Timer thread is able to read gui control values just fine (unlike this guy: can a worker thread read a control in the GUI?) Question 1: Given the cardinal rule of threads, should I be using Invoke/BeginInvoke to read form control values? And does this make it more thread-safe? The background to this question stems from a problem my app is having. It seems to randomly corrupt form controls another thread is referencing. (see question 2) Question 2: I have a second thread that needs to update form control values so I Invoke/BeginInvoke to update those values. Well this same thread needs a reference to those controls so it can update them. It holds a list of these controls (say DataGridViewRow objects). Sometimes (not always), the DataGridViewRow reference gets "corrupt". What I mean by corrupt, is the reference is still valid, but some of the DataGridViewRow properties are null (ex: row.Cells). Is this caused by question 1 or can you give me any tips on why this might be happening? Here's some code (the last line has the problem): public partial class MyForm : Form { void Timer_Elapsed(object sender) { // we're on a new thread (this function gets called every few seconds) UpdateUiHelper updateUiHelper = new UpdateUiHelper(this); foreach (DataGridViewRow row in dataGridView1.Rows) { object[] values = GetValuesFromDb(); updateUiHelper.UpdateRowValues(row, values[0]); } // .. do other work here updateUiHelper.UpdateUi(); } } public class UpdateUiHelper { private readonly Form _form; private Dictionary<DataGridViewRow, object> _rows; private delegate void RowDelegate(DataGridViewRow row); private readonly object _lockObject = new object(); public UpdateUiHelper(Form form) { _form = form; _rows = new Dictionary<DataGridViewRow, object>(); } public void UpdateRowValues(DataGridViewRow row, object value) { if (_rows.ContainsKey(row)) _rows[row] = value; else { lock (_lockObject) { _rows.Add(row, value); } } } public void UpdateUi() { foreach (DataGridViewRow row in _rows.Keys) { SetRowValueThreadSafe(row); } } private void SetRowValueThreadSafe(DataGridViewRow row) { if (_form.InvokeRequired) { _form.Invoke(new RowDelegate(SetRowValueThreadSafe), new object[] { row }); return; } // now we're on the UI thread object newValue = _rows[row]; row.Cells[0].Value = newValue; // randomly errors here with NullReferenceException, but row is never null! }

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  • How to insert into data base using multi threading programming [closed]

    - by user1196650
    I am having a method and that method needs to do the following thing: It has to insert records into a database. No insert is done for the same table again. All inserts are into different tables. I need a multi threading logic which inserts the details into db using different threads. I am using oracle db and driver configuration and remaining stuff are perfect. Please help me with an efficient answer. Can anyone could provide me with a skeleton logic of the program.

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  • Using two threads and controlling one from the other in java?

    - by sidra
    Can someone please help me out. I need to use two threads in a way that one thread will run permanently while(true) and will keep track of a positioning pointer (some random value coming in form a method). This thread has a logic, if the value equals something, it should start the new thread. And if the value does not equal it should stop the other thread. Can someone give me some code snippet (block level) about how to realize this?

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