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  • Thread loses Message after wait() and notify()

    - by fugu2.0
    Hey Guys! I have a problem handling messages in a Thread. My run-method looks like this public void run() { Looper.prepareLooper(); parserHandler = new Handler { public void handleMessage(Message msg) { Log.i("","id from message: "+msg.getData.getString("id")); // handle message this.wait(); } } } I have several Activities sending messages to this thread, like this: Message parserMessage = new Message(); Bundle data = new Bundle(); data.putString("id", realId); data.putString("callingClass", "CategoryList"); parserMessage.setData(data); parserMessage.what = PARSE_CATEGORIES_OR_PRODUCTS; parserHandler = parser.getParserHandler(); synchronized (parserHandler) { parserHandler.notify(); Log.i("","message ID: " + parserMessage.getData().getString("id")); } parserHandler.sendMessage(parserMessage); The problem is that the run-method logs "id from message: null" though "message ID" has a value in the Log-statement. Why does the message "lose" it's data when being send to the thread? Has it something to do with the notify? Thanks for your help

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  • Thread Locking CollectionViewSource

    - by Robert
    I added an event handler to my code and it broke all access to the CollectionViewSources in the SystemHTA class saying "The calling thread cannot access this object because a different thread owns it". My class was working when "this.systemHTA = new SystemHTA();" was placed outside of the DeviceManager_StateChanged() function. public partial class MainWindow : Window { private DeviceManager DeviceManager = DeviceManager.Instance; public SystemHTA systemHTA; public MainWindow() { InitializeComponent(); } private void Window_Loaded(object sender, RoutedEventArgs e) { DeviceManager.StateChanged += new EventHandler<DeviceManagerStateChangedEventArgs>(DeviceManager_StateChanged); DeviceManager.Initialize(); } void DeviceManager_StateChanged(object sender, DeviceManagerStateChangedEventArgs e) { if (e.State == DeviceManagerState.Operational) { this.systemHTA = new SystemHTA(); } } private void button1_Click(object sender, RoutedEventArgs e) { this.systemHTA.GetViewSourceTest(); } } public class SystemHTA { private CollectionViewSource _deviceTestSource; public SystemHTA() { _deviceTestSource = new CollectionViewSource(); _deviceTestSource.Source = CreateLoadData<HWController>.ControllerCollection; } public void GetViewSourceTest() { ListCollectionView view = (ListCollectionView)_deviceTestSource.View; //This creates an error saying a thread already owns _deviceTestSource } }

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  • Boost::Thread linking error on OSX?

    - by gct
    So I'm going nuts trying to figure this one out. Here's my basic setup: I'm compiling a shared library with a bunch of core functionality that uses a lot of boost stuff. We'll call this library libpf_core.so. It's linked with the boost static libraries, specifically the python, system, filesystem, thread, and program_options libraries. This all goes swimmingly. Now, I have a little test program called test_socketio which is compiled into a shared library (it's loaded as a plugin at runtime). It uses some boost stuff like boost::bind and boost::thread, and it's linked again libpf_core.so (which has the boost libraries included remember). When I go to compile test_socketio though, out of all my plugins it gives me a linking error: [ Building test_socketio ] g++ -c -pg -g -O0 -I/usr/local/include -I../include test_socketio.cc -o test_socketio.o g++ -shared test_socketio.o -lpy_core -o test_socketio.so Undefined symbols: "boost::lock_error::lock_error()", referenced from: boost::unique_lock<boost::mutex>::lock() in test_socketio.o ld: symbol(s) not found collect2: ld returned 1 exit status And I'm going crazy trying to figure out why this is. I've tried explicitly linking boost::thread into the plugin to no avail, tried ensuring that I'm using the boost headers associated with the libraries linked into libpf_core.so in case there was a conflict there. Is there something OSX specific regarding boost that I'm missing? In my searching on google I've seen a number of other people get this error but no one seems to have come up with a satisfactory solution.

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  • creating QT gui using a thread in c++?

    - by rashid
    I am trying to create this QT gui using a thread but no luck. Below is my code. Problem is gui never shows up. /*INCLUDES HERE... .... */ using namespace std; struct mainStruct { int s_argc;<br> char ** s_argv; }; typedef struct mainStruct mas; void *guifunc(void * arg); int main(int argc, char * argv[]) { mas m;<br> m.s_argc = argc;<br> m.s_argv = argv;<br> pthread_t threadGUI; //start a new thread for gui int result = pthread_create(&threadGUI, NULL, guifunc, (void *) &m); if (result) {<br> printf("Error creating gui thread"); exit(0); } return 0; } void *guifunc(void * arg) { mas m = *(mas *)arg; QApplication app(m.s_argc,m.s_argv); //object instantiation<br> guiClass *gui = new guiClass(); //show gui<br> gui->show(); app.exec(); <br> }

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  • Debugging instance of another thread altering my data

    - by Mick
    I have a huge global array of structures. Some regions of the array are tied to individual threads and those threads can modify their regions of the array without having to use critical sections. But there is one special region of the array which all threads may have access to. The code that accesses these parts of the array needs to carefully use critical sections (each array element has its own critical section) to prevent any possibility of two threads writing to the structure simultaneously. Now I have a mysterious bug I am trying to chase, it is occurring unpredictably and very infrequently. It seems that one of the structures is being filled with some incorrect number. One obvious explanation is that another thread has accidentally been allowed to set this number when it should be excluded from doing so. Unfortunately it seems close to impossible to track this bug. The array element in which the bad data appears is different each time. What I would love to be able to do is set some kind of trap for the bug as follows: I would enter a critical section for array element N, then I know that no other thread should be able to touch the data, then (until I exit the critical section) set some kind of flag to a debugging tool saying "if any other thread attempts to change the data here please break and show me the offending patch of source code"... but I suspect no such tool exists... or does it? Or is there some completely different debugging methodology that I should be employing.

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  • WP7 BarcodeManager - Invalid cross-thread access

    - by rpf
    I'm trying to use Windows Phone 7 Silverlight ZXing Barcode Scanning Library but I'm having some problems. I'm using a background worker to check the image, but when I do this: WP7BarcodeManager.ScanBarcode(this.Image, BarcodeResults_Finished); The code throws an exception: Invalid cross-thread access. Here is my code... void photoChooserTask_Completed(object sender, PhotoResult e) { if (e.TaskResult == TaskResult.OK) { ShowImage(); System.Windows.Media.Imaging.BitmapImage bmp = new System.Windows.Media.Imaging.BitmapImage(); bmp.SetSource(e.ChosenPhoto); imgCapture.Source = bmp; this.Image = new BitmapImage(); this.Image.SetSource(e.ChosenPhoto); progressBar.Visibility = System.Windows.Visibility.Visible; txtStatus.Visibility = System.Windows.Visibility.Collapsed; worker.RunWorkerAsync(); } else ShowMain(); } void worker_DoWork(object sender, DoWorkEventArgs e) { try { Thread.Sleep(2000); WP7BarcodeManager.ScanMode = com.google.zxing.BarcodeFormat.UPC_EAN; WP7BarcodeManager.ScanBarcode(this.Image, BarcodeResults_Finished); } catch (Exception ex) { Debug.WriteLine("Error processing image.", ex); } } How can I solve this?

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  • boost thread pool

    - by Dtag
    I need a threadpool for my application, and I'd like to rely on standard (C++11 or boost) stuff as much as possible. I realize there is an unofficial(!) boost thread pool class, which basically solves what I need, however I'd rather avoid it because it is not in the boost library itself -- why is it still not in the core library after so many years? In some posts on this page and elsewhere, people suggested using boost::asio to achieve a threadpool like behavior. At first sight, that looked like what I wanted to do, however I found out that all implementations I have seen have no means to join on the currently active tasks, which makes it useless for my application. To perform a join, they send stop signal to all the threads and subsequently join them. However, that completely nullifies the advantage of threadpools in my use case, because that makes new tasks require the creation of a new thread. What I want to do is: ThreadPool pool(4); for (...) { for (int i=0;i<something;i++) pool.pushTask(...); pool.join(); // do something with the results } Can anyone suggest a solution (except for using the existing unofficial thread pool on sourceforge)? Is there anything in C++11 or core boost that can help me here? Thanks a lot

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  • Servlet that starts a thread only once for every visitor

    - by user858749
    Hey I want to implement a Java Servlet that starts a thread only once for every single user. Even on refresh it should not start again. My last approach brought me some trouble so no code^^. Any Suggestions for the layout of the servlet? public class LoaderServlet extends HttpServlet { // The thread to load the needed information private LoaderThread loader; // The last.fm account private String lfmaccount; public LoaderServlet() { super(); lfmaccount = ""; } @Override protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { if (loader != null) { response.setContentType("text/plain"); response.setHeader("Cache-Control", "no-cache"); PrintWriter out = response.getWriter(); out.write(loader.getStatus()); out.flush(); out.close(); } else { loader = new LoaderThread(lfmaccount); loader.start(); request.getRequestDispatcher("WEB-INF/pages/loader.jsp").forward( request, response); } } @Override protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { if (lfmaccount.isEmpty()) { lfmaccount = request.getSession().getAttribute("lfmUser") .toString(); } request.getRequestDispatcher("WEB-INF/pages/loader.jsp").forward( request, response); } } The jsp uses ajax to regularly post to the servlet and get the status. The thread just runs like 3 minutes, crawling some last.fm data.

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  • Pointer inside a struct / thread

    - by bruno
    Hi! I have this warning "warning: assignment from incompatible pointer type " in this line: data1->transformed_block[l] = &transformed_block[l]; - void print_message_function ( void *ptr ) { dt *data; data = (dt *) ptr; printf("Dentro da thread Numero0: %ld\n", data->L_norm_NewBlock); pthread_exit(0); } typedef struct data_thread { long L_norm_NewBlock; int Bsize_X; int Bsize_Y; int *transformed_block[MAX_LEVEL]; long L_norm_OrigBlock; } dt; void function() { int *transformed_block[MAX_LEVEL]; pthread_t thread1; dt *data1; pthread_attr_t attr; pthread_attr_init(&attr); //Fills structure data1 = (dt *) malloc(sizeof(dt)); data1->transformed_block[l] = &transformed_block[l]; data1->L_norm_NewBlock=0; data1->Bsize_Y = Bsize_Y; data1->Bsize_X = Bsize_X; pthread_create(&thread1, &attr, (void *) &print_message_function, (void *) &data1); } I want to get rid of that warning, and the values i get inside the thread are wrong. For example data1-L_norm_NewBlock=0; in the thread guives me a differente value (not 0 like it should be).

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  • Get the first and last posts in a thread

    - by Grampa
    I am trying to code a forum website and I want to display a list of threads. Each thread should be accompanied by info about the first post (the "head" of the thread) as well as the last. My current database structure is the following: threads table: id - int, PK, not NULL, auto-increment name - varchar(255) posts table: id - int, PK, not NULL, auto-increment thread_id - FK for threads The tables have other fields as well, but they are not relevant for the query. I am interested in querying threads and somehow JOINing with posts so that I obtain both the first and last post for each thread in a single query (with no subqueries). So far I am able to do it using multiple queries, and I have defined the first post as being: SELECT * FROM threads t LEFT JOIN posts p ON t.id = p.thread_id ORDER BY p.id LIMIT 0, 1 The last post is pretty much the same except for ORDER BY id DESC. Now, I could select multiple threads with their first or last posts, by doing: SELECT * FROM threads t LEFT JOIN posts p ON t.id = p.thread_id ORDER BY p.id GROUP BY t.id But of course I can't get both at once, since I would need to sort both ASC and DESC at the same time. What is the solution here? Is it even possible to use a single query? Is there any way I could change the structure of my tables to facilitate this? If this is not doable, then what tips could you give me to improve the query performance in this particular situation?

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  • how to edit controls in a system::thread

    - by Ian Lundberg
    I need to be able to add items to a listbox inside of a thread. Code is below. 1. ref class Work 2. { 3. public: 4. static void RecieveThread() 5. { 6. while (true) 7. { 8. ZeroMemory(cID, 64); 9. ZeroMemory(message, 256); 10. if(recv(sConnect, message, 256, NULL) != SOCKET_ERROR && recv(sConnect, cID, 64, NULL) != SOCKET_ERROR) 11. { 12. ID = atoi(cID); 13. String^ meep = gcnew String(message); 14. lbxMessages->Items->Add(meep); 15. check = 1; 16. } 17. } 18. } 19. }; I get the error Error: a nonstatic member reference must be relative to a specific object on line 14. Is there any way to get it to let me do that? Because if I try to use String^ meep; outside of that Thread it doesn't contain anything. It works PERFECT when I use it within the thread but not outside of it. I need to be able to add that message to the listbox. If anyone can help I would appreciate it.

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  • sqlobject: No connection has been defined for this thread or process

    - by Claudiu
    I'm using sqlobject in Python. I connect to the database with conn = connectionForURI(connStr) conn.makeConnection() This succeeds, and I can do queries on the connection: g_conn = conn.getConnection() cur = g_conn.cursor() cur.execute(query) res = cur.fetchall() This works as intended. However, I also defined some classes, e.g: class User(SQLObject): class sqlmeta: table = "gui_user" username = StringCol(length=16, alternateID=True) password = StringCol(length=16) balance = FloatCol(default=0) When I try to do a query using the class: User.selectBy(username="foo") I get an exception: ... File "c:\python25\lib\site-packages\SQLObject-0.12.4-py2.5.egg\sqlobject\main.py", line 1371, in selectBy conn = connection or cls._connection File "c:\python25\lib\site-packages\SQLObject-0.12.4-py2.5.egg\sqlobject\dbconnection.py", line 837, in __get__ return self.getConnection() File "c:\python25\lib\site-packages\SQLObject-0.12.4-py2.5.egg\sqlobject\dbconnection.py", line 850, in getConnection "No connection has been defined for this thread " AttributeError: No connection has been defined for this thread or process How do I define a connection for a thread? I just realized I can pass in a connection keyword which I can give conn to to make it work, but how do I get it to work if I weren't to do that?

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  • Is this function thread-safe?

    - by kiddo
    Hello all,I am learning multi-threading and for the sake of understanding I have wriiten a small function using multithreading...it works fine.But I just want to know if that thread is safe to use,did I followed the correct rule. void CThreadingEx4Dlg::OnBnClickedOk() { //in thread1 100 elements are copied to myShiftArray(which is a CStringArray) thread1 = AfxBeginThread((AFX_THREADPROC)MyThreadFunction1,this); WaitForSingleObject(thread1->m_hThread,INFINITE); //thread2 waits for thread1 to finish because thread2 is going to make use of myShiftArray(in which thread1 processes it first) thread2 = AfxBeginThread((AFX_THREADPROC)MyThreadFunction2,this); thread3 = AfxBeginThread((AFX_THREADPROC)MyThreadFunction3,this); } UINT MyThreadFunction1(LPARAM lparam) { CThreadingEx4Dlg* pthis = (CThreadingEx4Dlg*)lparam; pthis->MyFunction(0,100); return 0; } UINT MyThreadFunction2(LPARAM lparam) { CThreadingEx4Dlg* pthis = (CThreadingEx4Dlg*)lparam; pthis->MyCommonFunction(0,20); return 0; } UINT MyThreadFunction3(LPARAM lparam) { CThreadingEx4Dlg* pthis = (CThreadingEx4Dlg*)lparam; WaitForSingleObject(pthis->thread3->m_hThread,INFINITE); //here thread3 waits for thread 2 to finish so that thread can continue pthis->MyCommonFunction(21,40); return 0; } void CThreadingEx4Dlg::MyFunction(int minCount,int maxCount) { for(int i=minCount;i<maxCount;i++) { //assume myArray is a CStringArray and it has 100 elemnts added to it. //myShiftArray is a CStringArray -public to the class CString temp; temp = myArray.GetAt(i); myShiftArray.Add(temp); } } void CThreadingEx4Dlg::MyCommonFunction(int min,int max) { for(int i = min;i < max;i++) { CSingleLock myLock(&myCS,TRUE); CString temp; temp = myShiftArray.GetAt(i); //threadArray is CStringArray-public to the class threadArray.Add(temp); } myEvent.PulseEvent(); }

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  • Is the below thread pool implementation correct(C#3.0)

    - by Newbie
    Hi Experts, For the first time ever I have implemented thread pooling and I found it to be working. But I am not very sure about the way I have done is the appropriate way it is supposed to be. Would you people mind in spending some valuable time to check and let me know if my approach is correct or not? If you people find that the approach is incorrect , could you please help me out in writing the correct version. I have basicaly read How to use thread pool and based on what ever I have understood I have developed the below program as per my need public class Calculation { #region Private variable declaration ManualResetEvent[] factorManualResetEvent = null; #endregion public void Compute() { factorManualResetEvent = new ManualResetEvent[2]; for (int i = 0; i < 2; i++){ factorManualResetEvent[i] = new ManualResetEvent(false); ThreadPool.QueueUserWorkItem(ThreadPoolCallback, i);} //Wait for all the threads to complete WaitHandle.WaitAll(factorManualResetEvent); //Proceed with the next task(s) NEXT_TASK_TO_BE_EXECUTED(); } #region Private Methods // Wrapper method for use with thread pool. public void ThreadPoolCallback(Object threadContext) { int threadIndex = (int)threadContext; Method1(); Method2(); factorManualResetEvent[threadIndex].Set(); } private void Method1 () { //Code of method 1} private void Method2 () { //Code of method 2 } #endregion }

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  • How can I use timer to stop another thread? [on hold]

    - by Haoda Fu
    How can we stop another thread based on a timer? I was trying to use timer to stop another thread. But I didn't got a success. To better illustrate my point and for your easy to understand the key issue. I made the following sample example. Your help is really appreciated using System; using System.Collections.Generic; using System.Text; using System.Threading; using System.Timers; namespace TestCodes { public static class Program { private static Thread nT = new Thread(PrintABC); private static System.Timers.Timer aTimer; public static void Main() { aTimer = new System.Timers.Timer(1000); aTimer.Elapsed += TimerCallback; aTimer.Interval = 1000; aTimer.Enabled = true; nT.Start(); Console.ReadLine(); } private static void TimerCallback(Object o, ElapsedEventArgs e) { nT.Join(); Console.WriteLine("Complete the PrintABC"); GC.Collect(); } private static void PrintABC() { for (int iter = 1; iter < 300; iter++) { Console.WriteLine(iter+"abc"); Console.ReadKey(); //Thread.Sleep(100); } } } }

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  • Deadlock Analysis in NetBeans 8

    - by Geertjan
    Lock contention profiling is very important in multi-core environments. Lock contention occurs when a thread tries to acquire a lock while another thread is holding it, forcing it to wait. Lock contentions result in deadlocks. Multi-core environments have even more threads to deal with, causing an increased likelihood of lock contentions. In NetBeans 8, the NetBeans Profiler has new support for displaying detailed information about lock contention, i.e., the relationship between the threads that are locked. After all, whenever there's a deadlock, in any aspect of interaction, e.g., a political deadlock, it helps to be able to point to the responsible party or, at least, the order in which events happened resulting in the deadlock. As an example, let's take the handy Deadlock sample code from the Java Tutorial and look at the tools in NetBeans IDE for identifying and analyzing the code. The description of the deadlock is nice: Alphonse and Gaston are friends, and great believers in courtesy. A strict rule of courtesy is that when you bow to a friend, you must remain bowed until your friend has a chance to return the bow. Unfortunately, this rule does not account for the possibility that two friends might bow to each other at the same time. To help identify who bowed first or, at least, the order in which bowing took place, right-click the file and choose "Profile File". In the Profile Task Manager, make the choices below: When you have clicked Run, the Threads window shows the two threads are blocked, i.e., the red "Monitor" lines tell you that the related threads are blocked while trying to enter a synchronized method or block: But which thread is holding the lock? Which one is blocked by the other? The above visualization does not answer these questions. New in NetBeans 8 is that you can analyze the deadlock in the new Lock Contention window to determine which of the threads is responsible for the lock: Here is the code that simulates the lock, very slightly tweaked at the end, where I use "setName" on the threads, so that it's even easier to analyze the threads in the relevant NetBeans tools. Also, I converted the anonymous inner Runnables to lambda expressions. package org.demo; public class Deadlock { static class Friend { private final String name; public Friend(String name) { this.name = name; } public String getName() { return this.name; } public synchronized void bow(Friend bower) { System.out.format("%s: %s" + " has bowed to me!%n", this.name, bower.getName()); bower.bowBack(this); } public synchronized void bowBack(Friend bower) { System.out.format("%s: %s" + " has bowed back to me!%n", this.name, bower.getName()); } } public static void main(String[] args) { final Friend alphonse = new Friend("Alphonse"); final Friend gaston = new Friend("Gaston"); Thread t1 = new Thread(() -> { alphonse.bow(gaston); }); t1.setName("Alphonse bows to Gaston"); t1.start(); Thread t2 = new Thread(() -> { gaston.bow(alphonse); }); t2.setName("Gaston bows to Alphonse"); t2.start(); } } In the above code, it's extremely likely that both threads will block when they attempt to invoke bowBack. Neither block will ever end, because each thread is waiting for the other to exit bow. Note: As you can see, it really helps to use "Thread.setName", everywhere, wherever you're creating a Thread in your code, since the tools in the IDE become a lot more meaningful when you've defined the name of the thread because otherwise the Profiler will be forced to use thread names like "thread-5" and "thread-6", i.e., based on the order of the threads, which is kind of meaningless. (Normally, except in a simple demo scenario like the above, you're not starting the threads in the same class, so you have no idea at all what "thread-5" and "thread-6" mean because you don't know the order in which the threads were started.) Slightly more compact: Thread t1 = new Thread(() -> { alphonse.bow(gaston); },"Alphonse bows to Gaston"); t1.start(); Thread t2 = new Thread(() -> { gaston.bow(alphonse); },"Gaston bows to Alphonse"); t2.start();

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  • Why does C# thread die?

    - by JackN
    This is my 1st C# project so I may be doing something obviously improper in the code below. I am using .NET, WinForms (I think), and this is a desktop application until I get the bugs out. UpdateGui() uses Invoke((MethodInvoker)delegate to update various GUI controls based on received serial data and sends a GetStatus() command out the serial port 4 times a second. Thread Read() reads the response from serial port whenever it arrives which should be near immediate. SerialPortFixer is a SerialPort IOException Workaround in C# I found at http://zachsaw.blogspot.com/2010/07/serialport-ioexception-workaround-in-c.html. After one or both threads die I'll see something like The thread 0x1288 has exited with code 0 (0x0). in the debug code output. Why do UpdateGui() and/or Read() eventually die? public partial class UpdateStatus : Form { private readonly byte[] Command = new byte[32]; private readonly byte[] Status = new byte[32]; readonly Thread readThread; private static readonly Mutex commandMutex = new Mutex(); private static readonly Mutex statusMutex = new Mutex(); ... public UpdateStatus() { InitializeComponent(); SerialPortFixer.Execute("COM2"); if (serialPort1.IsOpen) { serialPort1.Close(); } try { serialPort1.Open(); } catch (Exception e) { labelWarning.Text = LOST_COMMUNICATIONS + e; labelStatus.Text = LOST_COMMUNICATIONS + e; labelWarning.Visible = true; } readThread = new Thread(Read); readThread.Start(); new Timer(UpdateGui, null, 0, 250); } static void ProcessStatus(byte[] status) { Status.State = (State) status[4]; Status.Speed = status[6]; // MSB Status.Speed *= 256; Status.Speed += status[5]; var Speed = Status.Speed/GEAR_RATIO; Status.Speed = (int) Speed; ... } public void Read() { while (serialPort1 != null) { try { serialPort1.Read(Status, 0, 1); if (Status[0] != StartCharacter[0]) continue; serialPort1.Read(Status, 1, 1); if (Status[1] != StartCharacter[1]) continue; serialPort1.Read(Status, 2, 1); if (Status[2] != (int)Command.GetStatus) continue; serialPort1.Read(Status, 3, 1); ... statusMutex.WaitOne(); ProcessStatus(Status); Status.update = true; statusMutex.ReleaseMutex(); } catch (Exception e) { Console.WriteLine(@"ERROR! Read() " + e); } } } public void GetStatus() { const int parameterLength = 0; // For GetStatus statusMutex.WaitOne(); Status.update = false; statusMutex.ReleaseMutex(); commandMutex.WaitOne(); if (!SendCommand(Command.GetStatus, parameterLength)) { Console.WriteLine(@"ERROR! SendCommand(GetStatus)"); } commandMutex.ReleaseMutex(); } private void UpdateGui(object x) { try { Invoke((MethodInvoker)delegate { Text = DateTime.Now.ToLongTimeString(); statusMutex.WaitOne(); if (Status.update) { if (Status.Speed > progressBarSpeed.Maximum) { Status.Speed = progressBarSpeed.Maximum; } progressBarSpeed.Value = Status.Speed; labelSpeed.Text = Status.Speed + RPM; ... } else { labelWarning.Text = LOST_COMMUNICATIONS; labelStatus.Text = LOST_COMMUNICATIONS; labelWarning.Visible = true; } statusMutex.ReleaseMutex(); GetStatus(); }); } catch (Exception e) { Console.WriteLine(@"ERROR! UpdateGui() " + e); } } }

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  • Can't get my head arround background workers in c#

    - by Connel
    I have wrote an application that syncs two folders together. The problem with the program is that it stops responding whilst copying files. A quick search of stack-overflow told me I need to use something called a background worker. I have read a few pages on the net about this but find it really hard to understand as I'm pretty new to programming. Below is the code for my application - how can I simply put all of the File.Copy(....) commands into their own background worker (if that's even how it works)? Below is the code for the button click event that runs the sub procedure and the sub procedure I wish to use a background worker on all the File.Copy lines. Button event: protected virtual void OnBtnSyncClicked (object sender, System.EventArgs e) { //sets running boolean to true booRunning=true; //sets progress bar to 0 prgProgressBar.Fraction = 0; //resets values used by progressbar dblCurrentStatus = 0; dblFolderSize = 0; //tests if user has entered the same folder for both target and destination if (fchDestination.CurrentFolder == fchTarget.CurrentFolder) { //creates message box MessageDialog msdSame = new MessageDialog(this, DialogFlags.Modal, MessageType.Error, ButtonsType.Close, "You cannot sync two folders that are the same"); //sets message box title msdSame.Title="Error"; //sets respone type ResponseType response = (ResponseType) msdSame.Run(); //if user clicks on close button or closes window then close message box if (response == ResponseType.Close || response == ResponseType.DeleteEvent) { msdSame.Destroy(); } return; } //tests if user has entered a target folder that is an extension of the destination folder // or if user has entered a desatination folder that is an extension of the target folder if (fchTarget.CurrentFolder.StartsWith(fchDestination.CurrentFolder) || fchDestination.CurrentFolder.StartsWith(fchTarget.CurrentFolder)) { //creates message box MessageDialog msdContains = new MessageDialog(this, DialogFlags.Modal, MessageType.Error, ButtonsType.Close, "You cannot sync a folder with one of its parent folders"); //sets message box title msdContains.Title="Error"; //sets respone type and runs message box ResponseType response = (ResponseType) msdContains.Run(); //if user clicks on close button or closes window then close message box if (response == ResponseType.Close || response == ResponseType.DeleteEvent) { msdContains.Destroy(); } return; } //gets folder size of target folder FileSizeOfTarget(fchTarget.CurrentFolder); //gets folder size of destination folder FileSizeOfDestination(fchDestination.CurrentFolder); //runs SyncTarget procedure SyncTarget(fchTarget.CurrentFolder); //runs SyncDestination procedure SyncDestination(fchDestination.CurrentFolder); //informs user process is complete prgProgressBar.Text = "Finished"; //sets running bool to false booRunning = false; } Sync sub-procedure: protected void SyncTarget (string strCurrentDirectory) { //string array of all the directories in directory string[] staAllDirectories = Directory.GetDirectories(strCurrentDirectory); //string array of all the files in directory string[] staAllFiles = Directory.GetFiles(strCurrentDirectory); //loop over each file in directory foreach (string strFile in staAllFiles) { //string of just the file's name and not its path string strFileName = System.IO.Path.GetFileName(strFile); //string containing directory in target folder string strDirectoryInsideTarget = System.IO.Path.GetDirectoryName(strFile).Substring(fchTarget.CurrentFolder.Length); //inform user as to what file is being copied prgProgressBar.Text="Syncing " + strFile; //tests if file does not exist in destination folder if (!File.Exists(fchDestination.CurrentFolder + "/" + strDirectoryInsideTarget + "/" + strFileName)) { //if file does not exist copy it to destination folder, the true below means overwrite if file already exists File.Copy (strFile, fchDestination.CurrentFolder + "/" + strDirectoryInsideTarget + "/" + strFileName, true); } //tests if file does exist in destination folder if (File.Exists(fchDestination.CurrentFolder + "/" + strDirectoryInsideTarget + "/" + strFileName)) { //long (number) that contains date of last write time of target file long lngTargetFileDate = File.GetLastWriteTime(strFile).ToFileTime(); //long (number) that contains date of last write time of destination file long lngDestinationFileDate = File.GetLastWriteTime(fchDestination.CurrentFolder + "/" + strDirectoryInsideTarget + "/" + strFileName).ToFileTime(); //tests if target file is newer than destination file if (lngTargetFileDate > lngDestinationFileDate) { //if it is newer then copy file from target folder to destination folder File.Copy (strFile, fchDestination.CurrentFolder + "/" + strDirectoryInsideTarget + "/" + strFileName, true); } } //gets current file size FileInfo FileSize = new FileInfo(strFile); //sets file's filesize to dblCurrentStatus and adds it to current total of files dblCurrentStatus = dblCurrentStatus + FileSize.Length; double dblPercentage = dblCurrentStatus/dblFolderSize; prgProgressBar.Fraction = dblPercentage; } //loop over each folder in target folder foreach (string strDirectory in staAllDirectories) { //string containing directories inside target folder but not any higher directories string strDirectoryInsideTarget = strDirectory.Substring(fchTarget.CurrentFolder.Length); //tests if directory does not exist inside destination folder if (!Directory.Exists(fchDestination.CurrentFolder + "/" + strDirectoryInsideTarget)) { //it directory does not exisit create it Directory.CreateDirectory(fchDestination.CurrentFolder + "/" + strDirectoryInsideTarget); } //run sync on all files in directory SyncTarget(strDirectory); } } Any help will be greatly appreciated as after this the program will pretty much be finished :D

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  • C# thread functions not properly sharing a static data member

    - by Umer
    I have a class as following public class ScheduledUpdater { private static Queue<int> PendingIDs = new Queue<int>(); private static bool UpdateThreadRunning = false; private static bool IsGetAndSaveScheduledUpdateRunning = false; private static DataTable ScheduleConfiguration; private static Thread updateRefTableThread; private static Thread threadToGetAndSaveScheduledUpdate; public static void ProcessScheduledUpdates(int ID) { //do some stuff // if ( updateRefTableThread not already running) // execute updateRefTableThread = new Thread(new ThreadStart(UpdateSchedulingRefTableInThrear)); // execute updateRefTableThread.Start(); //do some stuff GetAndSaveScheduledUpdate(ID) } private static void UpdateSchedulingRefTableInThrear() { UpdateSchedulingRefTable(); } public static void UpdateSchedulingRefTable() { // read DB and update ScheduleConfiguration string query = " SELECT ID,TimeToSendEmail FROM TBLa WHERE MODE = 'WebServiceOrder' AND BDELETE = false "; clsCommandBuilder commandBuilder = new clsCommandBuilder(); DataSet ds = commandBuilder.GetDataSet(query); if (ds != null && ds.Tables.Count > 0 && ds.Tables[0].Rows.Count > 0) { List<string> lstIDs = new List<string>(); for (int i = 0; i < ds.Tables[0].Rows.Count; i++) { lstIDs.Add(ds.Tables[0].Rows[i]["ID"].ToString()); if (LastEmailSend.Contains(ds.Tables[0].Rows[i]["ID"].ToString())) LastEmailSend[ds.Tables[0].Rows[i]["ID"].ToString()] = ds.Tables[0].Rows[i]["TimeToSendEmail"].ToString(); else LastEmailSend.Add(ds.Tables[0].Rows[i]["ID"].ToString(), ds.Tables[0].Rows[i]["TimeToSendEmail"].ToString()); } if (lstIDs.Count > 0) { string Ids = string.Join(",", lstIDs.ToArray()).Trim(','); dhDBNames dbNames = new dhDBNames(); dbNames.Default_DB_Name = dbNames.ControlDB; dhGeneralPurpose dhGeneral = new dhGeneralPurpose(); dhGeneral.StringDH = Ids; DataSet result = commandBuilder.GetDataSet(dbNames, (object)dhGeneral, "xmlGetConfigurations"); if (result != null && result.Tables.Count > 0) { if (ScheduleConfiguration != null) ScheduleConfiguration.Clear(); ScheduleConfiguration = result.Tables[0]; } } } } public static void GetAndSaveScheduledUpdate(int ID) { //use ScheduleConfiguration if (ScheduleConfiguration == null)[1] UpdateSchedulingRefTable(); DataRow[] result = ScheduleConfiguration.Select("ID = "+ID); //then for each result row, i add this to a static Queue PendingIDs } } The function UpdateSchedulingRefTable can be called any time from outside world (for instance if someone updates the schedule configuration manually) ProcessScheduledUpdates is called from a windows service every other minute. Problem: Datatable ScheduleConfiguration is updated in the UpdateSchedulingRefTable (called from outside world - say manually) but when i try to use Datatable ScheduleConfiguration in GetAndSaveScheduledUpdate, i get the older version of values.... What am I missing in this stuff??? About EDIT: I thought the stuff i have not shown is quite obvious and possibly not desired, perhaps my structure is wrong :) and sorry for incorrect code previously, i made a simple function call as a thread initialization... sorry for my code indentation too because i don't know how to format whole block...

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  • Update UI from an event with a thread

    - by tyrone-tudehope
    Im working on a small application to try out an idea that I have. The idea is to periodically update the UI when event of some sort occurs. In the demo I've created, I'm updating a ProgressDialog every 2 seconds for 15 turns. The problem I am having, which I don't quite understand is that when an event is handled, I send a message to the handler which is supposed to update the message in the ProgressDialog. When this happens however, I get an exception which states that I can't update the UI from that thread. The following code appears in my Activity: ProgressDialog diag; String diagMessage = "Started loading..."; final static int MESSAGE_DATA_RECEIVED = 0; final static int MESSAGE_RECEIVE_COMPLETED = 1; final Handler handler = new Handler(){ @Override public void handleMessage(Message msg){ diag.setMessage(diagMessage); switch(msg.what){ case MESSAGE_DATA_RECEIVED: break; case MESSAGE_RECEIVE_COMPLETED: dismissDialog(); killDialog(); break; } } }; Boolean isRunning = false; /** * Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setupDialog(); if(isRunning){ showDialog(); } setContentView(R.layout.main); } void setupDialog(){ if(diag == null){ diag = new ProgressDialog(ThreadLoading.this); diag.setMessage(diagMessage); } } void showDialog(){ isRunning = true; if(diag != null && !diag.isShowing()){ diag.show(); } } void dismissDialog(){ if(diag != null && diag.isShowing()){ diag.dismiss(); } } void killDialog(){ isRunning = false; } public void onStart(){ super.onStart(); showDialog(); Thread background = new Thread(new Runnable(){ public void run(){ try{ final ThreadRunner tr = new ThreadRunner(); tr.setOnDataReceivedListener(new ThreadRunner.OnDataReceivedListener(){ public void onDataReceived(String message){ diagMessage = message; handler.handleMessage(handler.obtainMessage(MESSAGE_DATA_RECEIVED)); } }); tr.setOnDataDownloadCompletedEventListener(new ThreadRunner.OnDataDownloadCompletedListener(){ public void onDataDownloadCompleted(String message){ diagMessage = message; handler.handleMessage(handler.obtainMessage(MESSAGE_RECEIVE_COMPLETED)); } }); tr.runProcess(); } catch(Throwable t){ throw new RuntimeException(t); } } }); background.start(); } @Override public void onPause(){ super.onPause(); dismissDialog(); } For curiosity sake, here's the code for the ThreadRunner class: public interface OnDataReceivedListener { public void onDataReceived(String message); } public interface OnDataDownloadCompletedListener { public void onDataDownloadCompleted(String message); } private OnDataReceivedListener onDataReceivedEventListener; private OnDataDownloadCompletedListener onDataDownloadCompletedEventListener; int maxLoop = 15; int loopCount = 0; int sleepTime = 2000; public void setOnDataReceivedListener(OnDataReceivedListener onDataReceivedListener){ this.onDataReceivedEventListener = onDataReceivedListener; } public void setOnDataDownloadCompletedEventListener(OnDataDownloadCompletedListener onDataDownloadCompletedListener){ this.onDataDownloadCompletedEventListener = onDataDownloadCompletedListener; } public void runProcess(){ for(loopCount = 0; loopCount < maxLoop; loopCount++){ try{ Thread.sleep(sleepTime); onDataReceivedEventListener.onDataReceived(Integer.toString(loopCount)); } catch(Throwable t){ throw new RuntimeException(t); } } onDataDownloadCompletedEventListener.onDataDownloadCompleted("Download is completed"); } Am I missing something? The logic makes sense to me and it looks like everything should work, I'm using a handler to update the UI like it is recommended. Any help will be appreciated. Thanks, Tyrone P.S. I'm developing for Android 1.5

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  • REST WCF service locks thread when called using AJAX in an ASP.Net site

    - by Jupaol
    I have a WCF REST service consumed in an ASP.Net site, from a page, using AJAX. I want to be able to call methods from my service async, which means I will have callback handlers in my javascript code and when the methods finish, the output will be updated. The methods should run in different threads, because each method will take different time to complete their task I have the code semi-working, but something strange is happening because the first time I execute the code after compiling, it works, running each call in a different threads but subsequent calls blocs the service, in such a way that each method call has to wait until the last call ends in order to execute the next one. And they are running on the same thread. I have had the same problem before when I was using Page Methods, and I solved it by disabling the session in the page but I have not figured it out how to do the same when consuming WCF REST services Note: Methods complete time (running them async should take only 7 sec and the result should be: Execute1 - Execute3 - Execute2) Execute1 -- 2 sec Execute2 -- 7 sec Execute3 -- 4 sec Output After compiling Output subsequent calls (this is the problem) I will post the code...I'll try to simplify it as much as I can Service Contract [ServiceContract( SessionMode = SessionMode.NotAllowed )] public interface IMyService { // I have other 3 methods like these: Execute2 and Execute3 [OperationContract] [WebInvoke( RequestFormat = WebMessageFormat.Json, ResponseFormat = WebMessageFormat.Json, UriTemplate = "/Execute1", Method = "POST")] string Execute1(string param); } [AspNetCompatibilityRequirements(RequirementsMode = AspNetCompatibilityRequirementsMode.Allowed)] [ServiceBehavior( InstanceContextMode = InstanceContextMode.PerCall )] public class MyService : IMyService { // I have other 3 methods like these: Execute2 (7 sec) and Execute3(4 sec) public string Execute1(string param) { var t = Observable.Start(() => Thread.Sleep(2000), Scheduler.NewThread); t.First(); return string.Format("Execute1 on: {0} count: {1} at: {2} thread: {3}", param, "0", DateTime.Now.ToString(), Thread.CurrentThread.ManagedThreadId.ToString()); } } ASPX page <%@ Page EnableSessionState="False" Title="Home Page" Language="C#" MasterPageFile="~/Site.master" AutoEventWireup="true" CodeBehind="Default.aspx.cs" Inherits="RestService._Default" %> <asp:Content ID="HeaderContent" runat="server" ContentPlaceHolderID="HeadContent"> <script type="text/javascript"> function callMethodAsync(url, data) { $("#message").append("<br/>" + new Date()); $.ajax({ cache: false, type: "POST", async: true, url: url, data: '"de"', contentType: "application/json", dataType: "json", success: function (msg) { $("#message").append("<br/>&nbsp;&nbsp;&nbsp;" + msg); }, error: function (xhr) { alert(xhr.responseText); } }); } $(function () { $("#callMany").click(function () { $("#message").html(""); callMethodAsync("/Execute1", "hello"); callMethodAsync("/Execute2", "crazy"); callMethodAsync("/Execute3", "world"); }); }); </script> </asp:Content> <asp:Content ID="BodyContent" runat="server" ContentPlaceHolderID="MainContent"> <input type="button" id="callMany" value="Post Many" /> <div id="message"> </div> </asp:Content> Web.config (relevant) <system.webServer> <modules runAllManagedModulesForAllRequests="true" /> </system.webServer> <system.serviceModel> <serviceHostingEnvironment aspNetCompatibilityEnabled="true" multipleSiteBindingsEnabled="true" /> <standardEndpoints> <webHttpEndpoint> <standardEndpoint name="" helpEnabled="true" automaticFormatSelectionEnabled="true" /> </webHttpEndpoint> </standardEndpoints> </system.serviceModel> Global.asax void Application_Start(object sender, EventArgs e) { RouteTable.Routes.Ignore("{resource}.axd/{*pathInfo}"); RouteTable.Routes.Add(new ServiceRoute("", new WebServiceHostFactory(), typeof(MyService))); }

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  • Java Thread execution on same data

    - by AR89
    first of all here is the code, you can just copy an paste import java.util.ArrayList; public class RepetionCounter implements Runnable{ private int x; private int y; private int[][] matrix; private int xCounter; private int yCounter; private ArrayList<Thread> threadArray; private int rowIndex; private boolean[] countCompleted; public RepetionCounter(int x, int y, int [][]matrix) { this.x = x; this.y = y; this.matrix = matrix; this.threadArray = new ArrayList<Thread>(matrix.length); this.rowIndex = 0; for(int i = 0; i < matrix.length; i++){ threadArray.add(new Thread(this)); } countCompleted = new boolean[matrix.length]; } public void start(){ for (int i = 0; i < threadArray.size(); i++){ threadArray.get(i).start(); this.rowIndex++; } } public void count(int rowIndex) { for(int i = 0; i < matrix[rowIndex].length; i++){ if (matrix[rowIndex][i] == x){ this.xCounter++; } else if (matrix[rowIndex][i] == y){ this.yCounter++; } } } @Override public void run() { count(this.rowIndex); countCompleted[this.rowIndex] = true; } public int getxCounter() { return xCounter; } public void setxCounter(int xCounter) { this.xCounter = xCounter; } public int getyCounter() { return yCounter; } public void setyCounter(int yCounter) { this.yCounter = yCounter; } public boolean[] getCountCompleted() { return countCompleted; } public void setCountCompleted(boolean[] countCompleted) { this.countCompleted = countCompleted; } public static void main(String args[]){ int[][] matrix = {{0,2,1}, {2,3,4}, {3,2,0}}; RepetionCounter rc = new RepetionCounter(0, 2, matrix); rc.start(); boolean ready = false; while(!ready){ for(int i = 0; i < matrix.length; i++){ if (rc.getCountCompleted()[i]){ ready = true; } else { ready = false; } } } if (rc.getxCounter() > rc.getyCounter()){ System.out.println("Thre are more x than y"); } else {System.out.println("There are:"+rc.getxCounter()+" x and:"+rc.getyCounter()+" y"); } } } What I want this code to do: I give to the object a matrix and tow numbers, and I want to know how much times these two numbers occurs in the matrix. I create as many thread as the number of rows of the matrix (that' why there is that ArrayList), so in this object I have k threads (supposing k is the number of rows), each of them count the occurrences of the two numbers. The problem is: if I run it for the first time everything work, but if I try to execute it another time I get and IndexOutOfBoundException, or a bad count of the occurrences, the odd thing is that if I get the error, and modify the code, after that it will works again just for once. Can you explain to me why is this happening?

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  • Android threading and database locking

    - by Sena Gbeckor-Kove
    Hi, We are using AsyncTasks to access database tables and cursors. Unfortunately we are seeing occasional exceptions regarding the database being locked. E/SQLiteOpenHelper(15963): Couldn't open iviewnews.db for writing (will try read-only): E/SQLiteOpenHelper(15963): android.database.sqlite.SQLiteException: database is locked E/SQLiteOpenHelper(15963): at android.database.sqlite.SQLiteDatabase.native_setLocale(Native Method) E/SQLiteOpenHelper(15963): at android.database.sqlite.SQLiteDatabase.setLocale(SQLiteDatabase.java:1637) E/SQLiteOpenHelper(15963): at android.database.sqlite.SQLiteDatabase.<init>(SQLiteDatabase.java:1587) E/SQLiteOpenHelper(15963): at android.database.sqlite.SQLiteDatabase.openDatabase(SQLiteDatabase.java:638) E/SQLiteOpenHelper(15963): at android.database.sqlite.SQLiteDatabase.openOrCreateDatabase(SQLiteDatabase.java:659) E/SQLiteOpenHelper(15963): at android.database.sqlite.SQLiteDatabase.openOrCreateDatabase(SQLiteDatabase.java:652) E/SQLiteOpenHelper(15963): at android.app.ApplicationContext.openOrCreateDatabase(ApplicationContext.java:482) E/SQLiteOpenHelper(15963): at android.content.ContextWrapper.openOrCreateDatabase(ContextWrapper.java:193) E/SQLiteOpenHelper(15963): at android.database.sqlite.SQLiteOpenHelper.getWritableDatabase(SQLiteOpenHelper.java:98) E/SQLiteOpenHelper(15963): at android.database.sqlite.SQLiteOpenHelper.getReadableDatabase(SQLiteOpenHelper.java:158) E/SQLiteOpenHelper(15963): at com.iview.android.widget.IViewNewsTopStoryWidget.initData(IViewNewsTopStoryWidget.java:73) E/SQLiteOpenHelper(15963): at com.iview.android.widget.IViewNewsTopStoryWidget.updateNewsWidgets(IViewNewsTopStoryWidget.java:121) E/SQLiteOpenHelper(15963): at com.iview.android.async.GetNewsTask.doInBackground(GetNewsTask.java:338) E/SQLiteOpenHelper(15963): at com.iview.android.async.GetNewsTask.doInBackground(GetNewsTask.java:1) E/SQLiteOpenHelper(15963): at android.os.AsyncTask$2.call(AsyncTask.java:185) E/SQLiteOpenHelper(15963): at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:256) E/SQLiteOpenHelper(15963): at java.util.concurrent.FutureTask.run(FutureTask.java:122) E/SQLiteOpenHelper(15963): at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:648) E/SQLiteOpenHelper(15963): at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:673) E/SQLiteOpenHelper(15963): at java.lang.Thread.run(Thread.java:1060) Does anybody have a general example for code which writes to a database from a different thread than the one reading and how can we ensure thread safety. One suggestion I've had is to use a ContentProvider, as this would handle the access of the database from multiple threads. I am going to look at this, but is this the recommended method of handling such a problem? It seems rather heavyweight considering we're talking about in front or behind Thanks in advance.

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  • Python Socket Getting Connection Reset

    - by Ian
    I created a threaded socket listener that stores newly accepted connections in a queue. The socket threads then read from the queue and respond. For some reason, when doing benchmarking with 'ab' (apache benchmark) using a concurrency of 2 or more, I always get a connection reset before it's able to complete the benchmark (this is taking place locally, so there's no external connection issue). class server: _ip = '' _port = 8888 def __init__(self, ip=None, port=None): if ip is not None: self._ip = ip if port is not None: self._port = port self.server_listener(self._ip, self._port) def now(self): return time.ctime(time.time()) def http_responder(self, conn, addr): httpobj = http_builder() httpobj.header('HTTP/1.1 200 OK') httpobj.header('Content-Type: text/html; charset=UTF-8') httpobj.header('Connection: close') httpobj.body("Everything looks good") data = httpobj.generate() sent = conn.sendall(data) def http_thread(self, id): self.log("THREAD %d: Starting Up..." % id) while True: conn, addr = self.q.get() ip, port = addr self.log("THREAD %d: responding to request: %s:%s - %s" % (id, ip, port, self.now())) self.http_responder(conn, addr) self.q.task_done() conn.close() def server_listener(self, host, port): self.q = Queue.Queue(0) sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM) sock.bind( (host, port) ) sock.listen(5) for i in xrange(4): #thread count thread.start_new(self.http_thread, (i+1, )) while True: self.q.put(sock.accept()) sock.close() server('', 9999) When running the benchmark, I get totally random numbers of good requests before it errors out, usually between 4 and 500. Edit: Took me a while to figure it out, but the problem was in sock.listen(5). Because I was using apache benchmark with a higher concurrency (5 and up) it was causing the backlog of connections to pile up, at which point the connections started getting dropped by the socket.

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  • Atomic Instructions and Variable Update visibility

    - by dsimcha
    On most common platforms (the most important being x86; I understand that some platforms have extremely difficult memory models that provide almost no guarantees useful for multithreading, but I don't care about rare counter-examples), is the following code safe? Thread 1: someVariable = doStuff(); atomicSet(stuffDoneFlag, 1); Thread 2: while(!atomicRead(stuffDoneFlag)) {} // Wait for stuffDoneFlag to be set. doMoreStuff(someVariable); Assuming standard, reasonable implementations of atomic ops: Is Thread 1's assignment to someVariable guaranteed to complete before atomicSet() is called? Is Thread 2 guaranteed to see the assignment to someVariable before calling doMoreStuff() provided it reads stuffDoneFlag atomically? Edits: The implementation of atomic ops I'm using contains the x86 LOCK instruction in each operation, if that helps. Assume stuffDoneFlag is properly cleared somehow. How isn't important. This is a very simplified example. I created it this way so that you wouldn't have to understand the whole context of the problem to answer it. I know it's not efficient.

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