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• Using Interlocked.Exchange(ref Enum, 1) to prevent re-entrancy [migrated]

  - by makerofthings7

  What options do I have for pending work that can't acquire a lock via the following sample? System.Threading.Interlocked.CompareExchange<TrustPointStatusEnum> (ref tp.TrustPointStatus, TrustPointStatusEnum.NotInitalized,TrustPointStatusEnum.Loading); Based on my research think I have the following options: I can use Threading.SpinWait (for very quick IO tasks) at the cost of CPU I can use Sleep() which has an unreliable wake up time I'm not sure of any other option, but what I want to make sure of is that all these options work with the .NET 4 async and await keywords, especially if I use Task to run them on a background thread

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• Why is multithreading often preferred for improving performance?

  - by user1849534

  I have a question, it's about why programmers seems to love concurrency and multi-threaded programs in general. I'm considering 2 main approaches here: an async approach basically based on signals, or just an async approach as called by many papers and languages like the new C# 5.0 for example, and a "companion thread" that manages the policy of your pipeline a concurrent approach or multi-threading approach I will just say that I'm thinking about the hardware here and the worst case scenario, and I have tested this 2 paradigms myself, the async paradigm is a winner at the point that I don't get why people 90% of the time talk about multi-threading when they want to speed up things or make a good use of their resources. I have tested multi-threaded programs and async program on an old machine with an Intel quad-core that doesn't offer a memory controller inside the CPU, the memory is managed entirely by the motherboard, well in this case performances are horrible with a multi-threaded application, even a relatively low number of threads like 3-4-5 can be a problem, the application is unresponsive and is just slow and unpleasant. A good async approach is, on the other hand, probably not faster but it's not worst either, my application just waits for the result and doesn't hangs, it's responsive and there is a much better scaling going on. I have also discovered that a context change in the threading world it's not that cheap in real world scenario, it's in fact quite expensive especially when you have more than 2 threads that need to cycle and swap among each other to be computed. On modern CPUs the situation it's not really that different, the memory controller it's integrated but my point is that an x86 CPUs is basically a serial machine and the memory controller works the same way as with the old machine with an external memory controller on the motherboard. The context switch is still a relevant cost in my application and the fact that the memory controller it's integrated or that the newer CPU have more than 2 core it's not bargain for me. For what i have experienced the concurrent approach is good in theory but not that good in practice, with the memory model imposed by the hardware, it's hard to make a good use of this paradigm, also it introduces a lot of issues ranging from the use of my data structures to the join of multiple threads. Also both paradigms do not offer any security abut when the task or the job will be done in a certain point in time, making them really similar from a functional point of view. According to the X86 memory model, why the majority of people suggest to use concurrency with C++ and not just an async approach ? Also why not considering the worst case scenario of a computer where the context switch is probably more expensive than the computation itself ?

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• Plagued by multithreaded bugs

  - by koncurrency

  On my new team that I manage, the majority of our code is platform, TCP socket, and http networking code. All C++. Most of it originated from other developers that have left the team. The current developers on the team are very smart, but mostly junior in terms of experience. Our biggest problem: multi-threaded concurrency bugs. Most of our class libraries are written to be asynchronous by use of some thread pool classes. Methods on the class libraries often enqueue long running taks onto the thread pool from one thread and then the callback methods of that class get invoked on a different thread. As a result, we have a lot of edge case bugs involving incorrect threading assumptions. This results in subtle bugs that go beyond just having critical sections and locks to guard against concurrency issues. What makes these problems even harder is that the attempts to fix are often incorrect. Some mistakes I've observed the team attempting (or within the legacy code itself) includes something like the following: Common mistake #1 - Fixing concurrency issue by just put a lock around the shared data, but forgetting about what happens when methods don't get called in an expected order. Here's a very simple example: void Foo::OnHttpRequestComplete(statuscode status) { m_pBar->DoSomethingImportant(status); } void Foo::Shutdown() { m_pBar->Cleanup(); delete m_pBar; m_pBar=nullptr; } So now we have a bug in which Shutdown could get called while OnHttpNetworkRequestComplete is occuring on. A tester finds the bug, captures the crash dump, and assigns the bug to a developer. He in turn fixes the bug like this. void Foo::OnHttpRequestComplete(statuscode status) { AutoLock lock(m_cs); m_pBar->DoSomethingImportant(status); } void Foo::Shutdown() { AutoLock lock(m_cs); m_pBar->Cleanup(); delete m_pBar; m_pBar=nullptr; } The above fix looks good until you realize there's an even more subtle edge case. What happens if Shutdown gets called before OnHttpRequestComplete gets called back? The real world examples my team has are even more complex, and the edge cases are even harder to spot during the code review process. Common Mistake #2 - fixing deadlock issues by blindly exiting the lock, wait for the other thread to finish, then re-enter the lock - but without handling the case that the object just got updated by the other thread! Common Mistake #3 - Even though the objects are reference counted, the shutdown sequence "releases" it's pointer. But forgets to wait for the thread that is still running to release it's instance. As such, components are shutdown cleanly, then spurious or late callbacks are invoked on an object in an state not expecting any more calls. There are other edge cases, but the bottom line is this: Multithreaded programming is just plain hard, even for smart people. As I catch these mistakes, I spend time discussing the errors with each developer on developing a more appropriate fix. But I suspect they are often confused on how to solve each issue because of the enormous amount of legacy code that the "right" fix will involve touching. We're going to be shipping soon, and I'm sure the patches we're applying will hold for the upcoming release. Afterwards, we're going to have some time to improve the code base and refactor where needed. We won't have time to just re-write everything. And the majority of the code isn't all that bad. But I'm looking to refactor code such that threading issues can be avoided altogether. One approach I am considering is this. For each significant platform feature, have a dedicated single thread where all events and network callbacks get marshalled onto. Similar to COM apartment threading in Windows with use of a message loop. Long blocking operations could still get dispatched to a work pool thread, but the completion callback is invoked on on the component's thread. Components could possibly even share the same thread. Then all the class libraries running inside the thread can be written under the assumption of a single threaded world. Before I go down that path, I am also very interested if there are other standard techniques or design patterns for dealing with multithreaded issues. And I have to emphasize - something beyond a book that describes the basics of mutexes and semaphores. What do you think? I am also interested in any other approaches to take towards a refactoring process. Including any of the following: Literature or papers on design patterns around threads. Something beyond an introduction to mutexes and semaphores. We don't need massive parallelism either, just ways to design an object model so as to handle asynchronous events from other threads correctly. Ways to diagram the threading of various components, so that it will be easy to study and evolve solutions for. (That is, a UML equivalent for discussing threads across objects and classes) Educating your development team on the issues with multithreaded code. What would you do?

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• WCF and Firewalls

  - by Amitd

  Hi guys, As a part of learning WCF, I was trying to use a simple WCF client-server code . http://weblogs.asp.net/ralfw/archive/2007/04/14/a-truely-simple-example-to-get-started-with-wcf.aspx but I'm facing strange issues.I was trying out the following. Client(My) IP address is : 192.168.2.5 (internal behind firewall) Server IP address is : 192.168.50.30 port : 9050 (internal behind firewall) Servers LIVE/External IP (on internet ) : 121.225.xx.xx (accessible from internet) When I specify the above I.P address of server(192.168.50.30), the client connects successfully and can call servers methods. Now suppose if I want to give my friend (outside network/on internet) the client with server's live I.P, i get an ENDPOINTNOTFOUND exceptions. Surprisingly if I run the above client specifying LIVE IP(121.225.xx.xx) of server i also get the same exception. I tried to debug the problem but haven't found anything. Is it a problem with the company firewall not forwarding my request? or is it a problem with the server or client . Is something needed to be added to the server/client to overcome the same problem? Or are there any settings on the firewall that need to be changed like port forwarding? (our network admin has configured the port to be accessible from the internet.) is it a authentication issue? Code is available at . http://www.ralfw.de/weblog/wcfsimple.txt http://weblogs.asp.net/ralfw/archive/2007/04/14/a-truely-simple-example-to-get-started-with-wcf.aspx i have just separated the client and server part in separate assemblies.rest is same. using System; using System.Collections.Generic; using System.Text; using System.ServiceModel; namespace WCFSimple.Contract { [ServiceContract] public interface IService { [OperationContract] string Ping(string name); } } namespace WCFSimple.Server { [ServiceBehavior(InstanceContextMode = InstanceContextMode.PerCall)] class ServiceImplementation : WCFSimple.Contract.IService { #region IService Members public string Ping(string name) { Console.WriteLine("SERVER - Processing Ping('{0}')", name); return "Hello, " + name; } #endregion } public class Program { private static System.Threading.AutoResetEvent stopFlag = new System.Threading.AutoResetEvent(false); public static void Main() { ServiceHost svh = new ServiceHost(typeof(ServiceImplementation)); svh.AddServiceEndpoint( typeof(WCFSimple.Contract.IService), new NetTcpBinding(), "net.tcp://localhost:8000"); svh.Open(); Console.WriteLine("SERVER - Running..."); stopFlag.WaitOne(); Console.WriteLine("SERVER - Shutting down..."); svh.Close(); Console.WriteLine("SERVER - Shut down!"); } public static void Stop() { stopFlag.Set(); } } } namespace WCFSimple { class Program { static void Main(string[] args) { Console.WriteLine("WCF Simple Demo"); // start server System.Threading.Thread thServer = new System.Threading.Thread(WCFSimple.Server.Program.Main); thServer.IsBackground = true; thServer.Start(); System.Threading.Thread.Sleep(1000); // wait for server to start up // run client ChannelFactory<WCFSimple.Contract.IService> scf; scf = new ChannelFactory<WCFSimple.Contract.IService>( new NetTcpBinding(), "net.tcp://localhost:8000"); WCFSimple.Contract.IService s; s = scf.CreateChannel(); while (true) { Console.Write("CLIENT - Name: "); string name = Console.ReadLine(); if (name == "") break; string response = s.Ping(name); Console.WriteLine("CLIENT - Response from service: " + response); } (s as ICommunicationObject).Close(); // shutdown server WCFSimple.Server.Program.Stop(); thServer.Join(); } } } Any help?

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• Python: nonblocking read from stdout of threaded subprocess

  - by sberry2A

  I have a script (worker.py) that prints unbuffered output in the form... 1 2 3 . . . n where n is some constant number of iterations a loop in this script will make. In another script (service_controller.py) I start a number of threads, each of which starts a subprocess using subprocess.Popen(stdout=subprocess.PIPE, ...); Now, in my main thread (service_controller.py) I want to read the output of each thread's worker.py subprocess and use it to calculate an estimate for the time remaining till completion. I have all of the logic working that reads the stdout from worker.py and determines the last printed number. The problem is that I can not figure out how to do this in a non-blocking way. If I read a constant bufsize then each read will end up waiting for the same data from each of the workers. I have tried numerous ways including using fcntl, select + os.read, etc. What is my best option here? I can post my source if needed, but I figured the explanation describes the problem well enough. Thanks for any help here. EDIT Adding sample code I have a worker that starts a subprocess. class WorkerThread(threading.Thread): def __init__(self): self.completed = 0 self.process = None self.lock = threading.RLock() threading.Thread.__init__(self) def run(self): cmd = ["/path/to/script", "arg1", "arg2"] self.process = subprocess.Popen(cmd, stdout=subprocess.PIPE, bufsize=1, shell=False) #flags = fcntl.fcntl(self.process.stdout, fcntl.F_GETFL) #fcntl.fcntl(self.process.stdout.fileno(), fcntl.F_SETFL, flags | os.O_NONBLOCK) def get_completed(self): self.lock.acquire(); fd = select.select([self.process.stdout.fileno()], [], [], 5)[0] if fd: self.data += os.read(fd, 1) try: self.completed = int(self.data.split("\n")[-2]) except IndexError: pass self.lock.release() return self.completed I then have a ThreadManager. class ThreadManager(): def __init__(self): self.pool = [] self.running = [] self.lock = threading.Lock() def clean_pool(self, pool): for worker in [x for x in pool is not x.isAlive()]: worker.join() pool.remove(worker) del worker return pool def run(self, concurrent=5): while len(self.running) + len(self.pool) > 0: self.clean_pool(self.running) n = min(max(concurrent - len(self.running), 0), len(self.pool)) if n > 0: for worker in self.pool[0:n]: worker.start() self.running.extend(self.pool[0:n]) del self.pool[0:n] time.sleep(.01) for worker in self.running + self.pool: worker.join() and some code to run it. threadManager = ThreadManager() for i in xrange(0, 5): threadManager.pool.append(WorkerThread()) threadManager.run() I have stripped out a log of the other code in hopes to try to pinpoint the issue.

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• FireandForget delegate - c#

  - by uno

  I came across this link, link text In the article, where the author has definition of this method static void WriteIt(string first, string second, int num) I changed that in my test app to this static void WriteIt(CustomerObject Customer) { fileIO.CreateFile(XMLUtil.Serialize(Customer)); } Where public static string Serialize(object o) { System.Xml.Serialization.XmlSerializerNamespaces ns = new System.Xml.Serialization.XmlSerializerNamespaces(); ns.Add("", ""); return Serialize(o, ns); } public static string Serialize(object o, XmlSerializerNamespaces ns) { try { using (System.IO.MemoryStream m = new System.IO.MemoryStream()) { //serialize messagelist to xml XmlSerializer serializer = new XmlSerializer(o.GetType(), ""); if (ns != null) serializer.Serialize(m, o, ns); else serializer.Serialize(m, o); m.Position = 0; byte[] b = new byte[m.Length]; m.Read(b, 0, b.Length); return System.Text.UTF8Encoding.UTF8.GetString(b); } } catch (Exception ex) { return "Ex = " + ex.ToString(); } } This method always gives an exception static void EndWrapperInvoke (IAsyncResult ar) { wrapperInstance.EndInvoke(ar); ar.AsyncWaitHandle.Close(); } Stacktrace: Server stack trace: at System.RuntimeMethodHandle._InvokeMethodFast(Object target, Object[] arguments, SignatureStruct& sig, MethodAttributes methodAttributes, RuntimeTypeHandle typeOwner) at System.RuntimeMethodHandle.InvokeMethodFast(Object target, Object[] arguments, Signature sig, MethodAttributes methodAttributes, RuntimeTypeHandle typeOwner) at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture, Boolean skipVisibilityChecks) at System.Delegate.DynamicInvokeImpl(Object[] args) at System.Delegate.DynamicInvoke(Object[] args) at SRC.FileMover.ThreadUtil.InvokeWrappedDelegate(Delegate d, Object[] args) at System.Runtime.Remoting.Messaging.StackBuilderSink._PrivateProcessMessage(IntPtr md, Object[] args, Object server, Int32 methodPtr, Boolean fExecuteInContext, Object[]& outArgs) at System.Runtime.Remoting.Messaging.StackBuilderSink.PrivateProcessMessage(RuntimeMethodHandle md, Object[] args, Object server, Int32 methodPtr, Boolean fExecuteInContext, Object[]& outArgs) at System.Runtime.Remoting.Messaging.StackBuilderSink.AsyncProcessMessage(IMessage msg, IMessageSink replySink) Exception rethrown at [0]: at System.Runtime.Remoting.Proxies.RealProxy.EndInvokeHelper(Message reqMsg, Boolean bProxyCase) at System.Runtime.Remoting.Proxies.RemotingProxy.Invoke(Object NotUsed, MessageData& msgData) at SRC.FileMover.ThreadUtil.DelegateWrapper.EndInvoke(IAsyncResult result) at SRC.FileMover.ThreadUtil.EndWrapperInvoke(IAsyncResult ar) at System.Runtime.Remoting.Messaging.AsyncResult.SyncProcessMessage(IMessage msg) at System.Runtime.Remoting.Messaging.StackBuilderSink.AsyncProcessMessage(IMessage msg, IMessageSink replySink) at System.Runtime.Remoting.Proxies.AgileAsyncWorkerItem.DoAsyncCall() at System.Runtime.Remoting.Proxies.AgileAsyncWorkerItem.ThreadPoolCallBack(Object o) at System.Threading._ThreadPoolWaitCallback.WaitCallback_Context(Object state) at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state) at System.Threading._ThreadPoolWaitCallback.PerformWaitCallbackInternal(_ThreadPoolWaitCallback tpWaitCallBack) at System.Threading._ThreadPoolWaitCallback.PerformWaitCallback(Object state) UPDATE 1: Trying to run my app and get the full exception. It seems like its happening at different locations. I will repost my ? again shortly. I think it may be wise if I can post my application. Can i upload a .zip file or is it better to just post the .cs code that I am using?

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• can create a new thread on goog-app-engine ..(python)

  - by zjm1126

  i use this code can crteate ,but someone say it can't create ,why ? class LogText(db.Model): content = db.StringProperty(multiline=True) class MyThread(threading.Thread): def __init__(self,threadname): threading.Thread.__init__(self, name=threadname) def run(self,request): log=LogText() log.content=request.POST.get('content',None) log.put() def Log(request): thr = MyThread('haha') thr.run(request) return HttpResponse('')

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• How to kill main thread from sub thread in Jython

  - by JeffGoetz

  I have a script that creates a thread which after 60 seconds (this thread) needs to kill the main thread. I`m not sure what command I can use to kill the main thread. I'm using Jython 2.5.1 and Thread.interrupt_main doesn't work. Here is the code: import threading def exitFunct(): #exit code here t = threading.Timer(60.0, exitFunct) t.start() for i in range(1, 3000): print i

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• Controllers and threads

  - by user72185

  Hi, I'm seeing this code in a project and I wonder if it is safe to do: (ASP.NET MVC 2.0) class MyController { void ActionResult SomeAction() { System.Threading.Thread newThread = new System.Threading.Thread(AsyncFunc); newThread.Start(); } void AsyncFunc() { string someString = HttpContext.Request.UrlReferrer.Authority + Url.Action("Index", new { controller = "AnotherAction" } ); } } Is the controller reused, possibly changing the content of HttpContext.Request and Url, or is this fine (except for not using the thread pool). Thanks for info!

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• Why does release mode affect on Thread.CurrentThread.CurrentCulture?

  - by satispunk

  Hi I have ASP .NET application. I set culture in Application_Begin request: System.Threading.Thread.CurrentThread.CurrentCulture = myCulture; System.Threading.Thread.CurrentThread.CurrentUICulture = myCulture; When I get current culture from page, it is myCulture in debug mode and it is "en-GB" in release mode. I don't understand why Release mode affects on Thread.CurrentThread.CurrentCulture I use VS2010 and .NET 4.0 Thanks

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• NHibernate Tutorial Run-Time Error: HibernateException

  - by Kashif

  I'm a newbie at NHibernate so please go easy on me if I have asked a stupid question... I am following the tutorial for NHibernate posted here and am getting a run-time error of type "HibernateException" The code in question looks like this: using System; using System.Collections.Generic; using System.Linq; using System.Text; using FirstSolution; using NHibernate.Cfg; using NHibernate.Tool.hbm2ddl; using NUnit.Framework; namespace FirstSolution.Tests { [TestFixture] public class GenerateSchema_Fixture { [Test] public void Can_generate_schema() { var cfg = new Configuration(); cfg.Configure(); cfg.AddAssembly(typeof(Product).Assembly); new SchemaExport(cfg).Execute(false, true, false); } } } The line I am getting the error at is: cfg.AddAssembly(typeof(Product).Assembly); The inner-most exception is: The IDbCommand and IDbConnection implementation in the assembly System.Data.SqlServerCe could not be found And here's my stack trace: at NHibernate.Connection.ConnectionProvider.ConfigureDriver(IDictionary`2 settings) at NHibernate.Connection.ConnectionProvider.Configure(IDictionary`2 settings) at NHibernate.Connection.ConnectionProviderFactory.NewConnectionProvider(IDictionary`2 settings) at NHibernate.Tool.hbm2ddl.SchemaExport.Execute(Action`1 scriptAction, Boolean export, Boolean justDrop) at NHibernate.Tool.hbm2ddl.SchemaExport.Execute(Boolean script, Boolean export, Boolean justDrop) at FirstSolution.Tests.GenerateSchema_Fixture.Can_generate_schema() in C:\Users\Kash\Documents\Visual Studio 2010\Projects\FirstSolution\FirstSolution\GenerateSchema_Fixture.cs:line 23 at HibernateUnitTest.Form1.button1_Click(Object sender, EventArgs e) in C:\Users\Kash\Documents\Visual Studio 2010\Projects\FirstSolution\HibernateUnitTest\Form1.cs:line 23 at System.Windows.Forms.Control.OnClick(EventArgs e) at System.Windows.Forms.Button.OnClick(EventArgs e) at System.Windows.Forms.Button.OnMouseUp(MouseEventArgs mevent) at System.Windows.Forms.Control.WmMouseUp(Message& m, MouseButtons button, Int32 clicks) at System.Windows.Forms.Control.WndProc(Message& m) at System.Windows.Forms.ButtonBase.WndProc(Message& m) at System.Windows.Forms.Button.WndProc(Message& m) at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m) at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m) at System.Windows.Forms.NativeWindow.DebuggableCallback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam) at System.Windows.Forms.UnsafeNativeMethods.DispatchMessageW(MSG& msg) at System.Windows.Forms.Application.ComponentManager.System.Windows.Forms.UnsafeNativeMethods.IMsoComponentManager.FPushMessageLoop(IntPtr dwComponentID, Int32 reason, Int32 pvLoopData) at System.Windows.Forms.Application.ThreadContext.RunMessageLoopInner(Int32 reason, ApplicationContext context) at System.Windows.Forms.Application.ThreadContext.RunMessageLoop(Int32 reason, ApplicationContext context) at System.Windows.Forms.Application.Run(Form mainForm) at HibernateUnitTest.Program.Main() in C:\Users\Kash\Documents\Visual Studio 2010\Projects\FirstSolution\HibernateUnitTest\Program.cs:line 18 at System.AppDomain._nExecuteAssembly(RuntimeAssembly assembly, String[] args) at System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String[] args) at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly() at System.Threading.ThreadHelper.ThreadStart_Context(Object state) at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean ignoreSyncCtx) at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state) at System.Threading.ThreadHelper.ThreadStart() I've made sure that System.Data.SqlServerCe has been referenced and that its Copy Local property is set to True. The error persists, however. Your help would be appreciated. Thanks.

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• C# : How to set test TCP connection timeout?

  - by Prince OfThief

  I try to test TCP connection with the following code. System.Threading.Thread t = new System.Threading.Thread(() => { using (TcpClient client = new TcpClient()) { client.Connect(ip, Convert.ToInt32(port)); } } }); t.Start(); How to set time out if the ip or port is invalid?

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• how to send some data to the Thread module on python and google-map-engine

  - by zjm1126

  from google.appengine.ext import db class Log(db.Model): content = db.StringProperty(multiline=True) class MyThread(threading.Thread): def run(self,request): #logs_query = Log.all().order('-date') #logs = logs_query.fetch(3) log=Log() log.content=request.POST.get('content',None) log.put() def Log(request): thr = MyThread() thr.start(request) return HttpResponse('') error is : Exception in thread Thread-1: Traceback (most recent call last): File "D:\Python25\lib\threading.py", line 486, in __bootstrap_inner self.run() File "D:\zjm_code\helloworld\views.py", line 33, in run log.content=request.POST.get('content',None) NameError: global name 'request' is not defined

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• how to write or create (when no exist) a file using python and Google AppEngine

  - by zjm1126

  this is my code: f = open('text/a.log', 'wb') f.write('hahaha') f.close() and it is not create a new file when not exist how to do this , thanks updated class MyThread(threading.Thread): def run(self): f = open('a.log', 'w') f.write('hahaha') f.close() error is : Traceback (most recent call last): File "D:\Python25\lib\threading.py", line 486, in __bootstrap_inner self.run() File "D:\zjm_code\helloworld\views.py", line 15, in run f = open('a.log', 'w') File "d:\Program Files\Google\google_appengine\google\appengine\tools\dev_appserver.py", line 1188, in __init__ raise IOError('invalid mode: %s' % mode) IOError: invalid mode: w

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• BSoD when creating threads

  - by Behrooz

  I am trying to create +5 threads synchronously so there shouldn't be any concurrency error. Code: System.Threading.Thread t = new System.Threading.Thread(proc); t.Start();//==t.BlueScreen(); t.Join(); Is darkness a feature ? I am doing something wrong? OS:Microsoft windows vista(unfortunately) x64 Language:C# 3.0|4.0 .Net version:3.5|4

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• how to make a thread of never stop, and write something to database every 10 second..

  - by zjm1126

  i using gae and django this is my code: class LogText(db.Model): content = db.StringProperty(multiline=True) class MyThread(threading.Thread): def __init__(self,threadname): threading.Thread.__init__(self, name=threadname) def run(self,request): log=LogText() log.content=request.POST.get('content',None) log.put() def Log(request): thr = MyThread('haha') thr.run(request) return HttpResponse('')

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• C++ Libraries similar to C#?

  - by cam

  I'm coming to C++ from a .Net background. Knowing how to use the Standard C++ Libraries, and all the syntax, I've never ventured further. Now I'm looking learning a bit more, such as what libraries are commonly used? I want to start getting into Threading but have no idea to start. Is there a library (similar to how .net has System.Threading) out there that will make it a bit easier? I'm specifically looking to do Linux based network programming.

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• using thread to load xsl transformation gives error.

  - by infant programmer

  I had to use threading to avoid "XSL Compilation time-out error" Now the problem I am facing is: It gives error, saying the output-string(generated as a result of transformation) is null!! Here is my C# code : [click_me] And the errors I am getting is copied in this text file : [click_me] And the original code without threading .. [click_me]

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• Programação paralela no .NET Framework 4 – Parte I

  - by anobre

  Introdução O avanço de tecnologia nos últimos anos forneceu, a baixo custo, acesso  a workstations com inúmeros CPUs. Facilmente encontramos hoje máquinas clientes com 2, 4 e até 8 núcleos, sem considerar os “super-servidores” com até 36 processadores :) Da wikipedia: A Unidade central de processamento (CPU, de acordo com as iniciais em inglês) ou o processador é a parte de um sistema de computador que executa as instruções de um programa de computador, e é o elemento primordial na execução das funções de um computador. Este termo tem sido usado na indústria de computadores pelo menos desde o início dos anos 1960[1]. A forma, desenho e implementação de CPUs têm mudado dramaticamente desde os primeiros exemplos, mas o seu funcionamento fundamental permanece o mesmo. Fazendo uma analogia, seria muito interessante delegarmos tarefas no mundo real que podem ser executadas independentemente a pessoas diferentes, atingindo desta forma uma  maior performance / produtividade na sua execução. A computação paralela se baseia na idéia que um problema maior pode ser dividido em problemas menores, sendo resolvidos de forma paralela. Este pensamento é utilizado há algum tempo por HPC (High-performance computing), e através das facilidades dos últimos anos, assim como a preocupação com consumo de energia, tornaram esta idéia mais atrativa e de fácil acesso a qualquer ambiente. No .NET Framework A plataforma .NET apresenta um runtime, bibliotecas e ferramentas para fornecer uma base de acesso fácil e rápido à programação paralela, sem trabalhar diretamente com threads e thread pool. Esta série de posts irá apresentar todos os recursos disponíveis, iniciando os estudos pela TPL, ou Task Parallel Library. Task Parallel Library A TPL é um conjunto de tipos localizados no namespace System.Threading e System.Threading.Tasks, a partir da versão 4 do framework. A partir da versão 4 do framework, o TPL é a maneira recomendada para escrever código paralelo e multithreaded. http://msdn.microsoft.com/en-us/library/dd460717(v=VS.100).aspx Task Parallelism O termo “task parallelism”, ou em uma tradução live paralelismo de tarefas, se refere a uma ou mais tarefas sendo executadas de forma simultanea. Considere uma tarefa como um método. A maneira mais fácil de executar tarefas de forma paralela é o código abaixo: Parallel.Invoke(() => TrabalhoInicial(), () => TrabalhoSeguinte()); O que acontece de verdade? Por trás nos panos, esta instrução instancia de forma implícita objetos do tipo Task, responsável por representar uma operação assíncrona, não exatamente paralela: public class Task : IAsyncResult, IDisposable É possível instanciar Tasks de forma explícita, sendo uma alternativa mais complexa ao Parallel.Invoke. var task = new Task(() => TrabalhoInicial()); task.Start(); Outra opção de instanciar uma Task e já executar sua tarefa é: var t = Task<int>.Factory.StartNew(() => TrabalhoInicialComValor());var t2 = Task<int>.Factory.StartNew(() => TrabalhoSeguinteComValor()); A diferença básica entre as duas abordagens é que a primeira tem início conhecido, mais utilizado quando não queremos que a instanciação e o agendamento da execução ocorra em uma só operação, como na segunda abordagem. Data Parallelism Ainda parte da TPL, o Data Parallelism se refere a cenários onde a mesma operação deva ser executada paralelamente em elementos de uma coleção ou array, através de instruções paralelas For e ForEach. A idéia básica é pegar cada elemento da coleção (ou array) e trabalhar com diversas threads concomitantemente. A classe-chave para este cenário é a System.Threading.Tasks.Parallel // Sequential version foreach (var item in sourceCollection) { Process(item); } // Parallel equivalent Parallel.ForEach(sourceCollection, item => Process(item)); Complicado né? :) Demonstração Acesse aqui um vídeo com exemplos (screencast). Cuidado! Apesar da imensa vontade de sair codificando, tome cuidado com alguns problemas básicos de paralelismo. Neste link é possível conhecer algumas situações. Abraços.

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• Silverlight Cream for January 13, 2011 -- #1026

  - by Dave Campbell

  In this Issue: András Velvárt, Tony Champion, Joost van Schaik, Jesse Liberty, Shawn Wildermuth, John Papa, Michael Crump, Sacha Barber, Alex Knight, Peter Kuhn, Senthil Kumar, Mike Hole, and WindowsPhoneGeek. Above the Fold: Silverlight: "Create Custom Speech Bubbles in Silverlight." Michael Crump WP7: "Architecting WP7 - Part 9 of 10: Threading" Shawn Wildermuth Expression Blend: "PathListBox: Text on the path" Alex Knight From SilverlightCream.com: Behaviors for accessing the Windows Phone 7 MarketPlace and getting feedback András Velvárt shares almost insider information about how to get some user interaction with your WP7 app in the form of feedback ... he has 4 behaviors taken straight from his very cool SufCube app that he's sharing. Reloading a Collection in the PivotViewer Tony Champion keeps working with the PivotViewer ... this time discussing the fact that you can't Reload or Refresh the current collection from the server ... at least not initially, but he did find one :) Tombstoning MVVMLight ViewModels with SilverlightSerializer on Windows Phone 7 Joost van Schaik takes a shot at helping us all with Tombstoning a WP7 app... he's using Mike Talbot's SilverlightSerializer and created extension methods for it for tombstoning that he's willing to share with us. Windows Phone From Scratch #17: MVVM Light Toolkit Soup To Nuts Part 2 Jesse Liberty is up to Part 17 in his WP7 series, and this is the 2nd post on MVVMLight and WP7, and is digging into behaviors. Architecting WP7 - Part 9 of 10: Threading Shawn Wildermuth is up to part 9 of 10 in his series on Architecting WP7 apps. This episode finds Shawn discussing Threading ... know how to use and choose between BackgroundWorker and ThreadPool? ... Shawn will explain. Silverlight TV 57: Performance Tuning Your Apps In the latest Silverlight TV, John Papa chats with Mike Cook about tuning your Silverlight app to get the performance up there where your users will be happy. Create Custom Speech Bubbles in Silverlight. Michael Crump's already gotten a lot of airplay out of this, but it's so cool.. comic-style callout shapes without using the dlls that you normally would... in other words, paths, and very cool hand-drawn looks on some too... very cool, Michael! Showcasing Cinch MVVM framework / PRISM 4 interoperability Sacha Barber has a post up on CodeProject that demonstratest using Cinch and Prism4 together... handily using MEF since Cinch relies on MEFedMVVM... this is a heck of a post... lots of code, lots of explanations. PathListBox: Text on the path Alex Knight keeps making this PathListBox series better ... this time he is putting text on the path... moving text... too cool, Alex! Windows Phone 7: Pinch Gesture Sample Peter Kuhn digs into the WP7 toolkit and examines GestureListener, pinch events, and clipping... examples and code supplied. How to change the StartPage of the Windows Phone 7 Application in Visual Studio 2010 ? Senthil Kumar discusses how to change the StartPage of your WP7 app, or get the program running if you happen to move or rename MainPage.xaml WP7 Text Boxes – OnEnter (my 1st Behaviour) Mike Hole has a post up about the issue with the keyboard appearing in front of the textbox, and maybe using the enter key to drop it... and he's developed a behavior for that process. WP7 ContextMenu in depth | Part1: key concepts and API WindowsPhoneGeek has some good articles that I haven't posted, but I'll catch up. This one is a nice tutorial on the WP7 Context menu... good explanation, diagrams, and code. Stay in the 'Light! Twitter SilverlightNews | Twitter WynApse | WynApse.com | Tagged Posts | SilverlightCream Join me @ SilverlightCream | Phoenix Silverlight User Group Technorati Tags: Silverlight    Silverlight 3    Silverlight 4    Windows Phone MIX10

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• Blob container creation exception ...

  - by Egon

  I get an exception every time I try to create a container for the blob using the following code blobStorageType = storageAccInfo.CreateCloudBlobClient(); ContBlob = blobStorageType.GetContainerReference(containerName); //everything fine till here ; next line creates an exception ContBlob.CreateIfNotExist(); Microsoft.WindowsAzure.StorageClient.StorageClientException was unhandled Message="One of the request inputs is out of range." Source="Microsoft.WindowsAzure.StorageClient" StackTrace: at Microsoft.WindowsAzure.StorageClient.Tasks.Task1.get_Result() at Microsoft.WindowsAzure.StorageClient.Tasks.Task1.ExecuteAndWait() at Microsoft.WindowsAzure.StorageClient.TaskImplHelper.ExecuteImplWithRetry[T](Func2 impl, RetryPolicy policy) at Microsoft.WindowsAzure.StorageClient.CloudBlobContainer.CreateIfNotExist(BlobRequestOptions options) at Microsoft.WindowsAzure.StorageClient.CloudBlobContainer.CreateIfNotExist() at WebRole1.BlobFun..ctor() in C:\Users\cloud\Documents\Visual Studio 2008\Projects\CloudBlob\WebRole1\BlobFun.cs:line 58 at WebRole1.BlobFun.calling1() in C:\Users\cloud\Documents\Visual Studio 2008\Projects\CloudBlob\WebRole1\BlobFun.cs:line 29 at AzureBlobTester.Program.Main(String[] args) in C:\Users\cloud\Documents\Visual Studio 2008\Projects\CloudBlob\AzureBlobTester\Program.cs:line 19 at System.AppDomain._nExecuteAssembly(Assembly assembly, String[] args) at System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String[] args) at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly() at System.Threading.ThreadHelper.ThreadStart_Context(Object state) at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state) at System.Threading.ThreadHelper.ThreadStart() InnerException: System.Net.WebException Message="The remote server returned an error: (400) Bad Request." Source="System" StackTrace: at System.Net.HttpWebRequest.EndGetResponse(IAsyncResult asyncResult) at Microsoft.WindowsAzure.StorageClient.EventHelper.ProcessWebResponse(WebRequest req, IAsyncResult asyncResult, EventHandler1 handler, Object sender) InnerException: Do you guys knw what is it that I am doing wrong ?

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• c# SmtpClient class not able to send email using gmail

  - by Sir Psycho

  Hi, I'm having trouble with this code sending email using my gmail account. Im pulling my hair out. The same settings work fine in Thunderbird. Heres the code. I've also tried port 465 with no luck. SmtpClient ss = new SmtpClient("smtp.gmail.com", 587); ss.Credentials = new NetworkCredential("username", "pass"); ss.EnableSsl = true; ss.Timeout = 10000; ss.DeliveryMethod = SmtpDeliveryMethod.Network; ss.UseDefaultCredentials = false; MailMessage mm = new MailMessage("[email protected]", "[email protected]", "subject here", "my body"); mm.BodyEncoding = UTF8Encoding.UTF8; mm.DeliveryNotificationOptions = DeliveryNotificationOptions.OnFailure; ss.Send(mm); Heres the error "The SMTP server requires a secure connection or the client was not authenticated. The server response was: 5.5.1 Authentication Required. Learn more at " Heres the stack trace at System.Net.Mail.MailCommand.CheckResponse(SmtpStatusCode statusCode, String response) at System.Net.Mail.MailCommand.Send(SmtpConnection conn, Byte[] command, String from) at System.Net.Mail.SmtpTransport.SendMail(MailAddress sender, MailAddressCollection recipients, String deliveryNotify, SmtpFailedRecipientException& exception) at System.Net.Mail.SmtpClient.Send(MailMessage message) at email_example.Program.Main(String[] args) in C:\Users\Vince\Documents\Visual Studio 2008\Projects\email example\email example\Program.cs:line 23 at System.AppDomain._nExecuteAssembly(Assembly assembly, String[] args) at System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String[] args) at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly() at System.Threading.ThreadHelper.ThreadStart_Context(Object state) at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state) at System.Threading.ThreadHelper.ThreadStart()

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• Castle ActiveRecord "Could not compile the mapping document: (string)"

  - by Nick

  Hi I am having getting an exception when trying to initialize ActiveRecord and I cannot figure out what I am missing. I am trying to convince the company I work for to use Castle ActiveRecord and it won't look good if I can't demonstrate how it works. I have work on projects before with Castle ActiveRecord and I had never experience this problem before. Thanks for your help The exception that I get is Stack Trace: at Castle.ActiveRecord.ActiveRecordStarter.AddXmlString(Configuration config, String xml, ActiveRecordModel model) at Castle.ActiveRecord.ActiveRecordStarter.AddXmlToNHibernateCfg(ISessionFactoryHolder holder, ActiveRecordModelCollection models) at Castle.ActiveRecord.ActiveRecordStarter.RegisterTypes(ISessionFactoryHolder holder, IConfigurationSource source, IEnumerable`1 types, Boolean ignoreProblematicTypes) at Castle.ActiveRecord.ActiveRecordStarter.Initialize(IConfigurationSource source, Type[] types) at ConsoleApplication1.Program.Main(String[] args) in C:\Projects\CastleDemo\ConsoleApplication1\Program.cs:line 20 at System.AppDomain._nExecuteAssembly(Assembly assembly, String[] args) at System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String[] args) at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly() at System.Threading.ThreadHelper.ThreadStart_Context(Object state) at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state) at System.Threading.ThreadHelper.ThreadStart() Inner Exception: {"Could not compile the mapping document: (string)"} Below is my configuration file: <add key="connection.driver_class" value="NHibernate.Driver.SqlClientDriver" /> <add key="dialect" value="NHibernate.Dialect.MsSql2000Dialect" /> <add key="connection.provider" value="NHibernate.Connection.DriverConnectionProvider" /> <add key="connection.connection_string" value="Data Source=SPIROS\SQLX;Initial Catalog=CastleDemo;Integrated Security=SSPI" /> <add key="proxyfactory.factory_class" value="NHibernate.ByteCode.Castle.ProxyFactoryFactory, NHibernate.ByteCode.Castle" /> and this is the main method that runs the initialization: static void Main(string[] args) { //Configure ActiveRecord source XmlConfigurationSource source = new XmlConfigurationSource("../../config.xml"); // //Initialazi ActiveRecord ActiveRecordStarter.Initialize( source, typeof(Product)); // //Create Schema ActiveRecordStarter.CreateSchema(); // }

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• Informix, NHibernate, TransactionScope interaction difficulties

  - by John Prideaux

  I have a small program that is trying to wrap an NHibernate insert into an Informix database in a TransactionScope object using the Informix .NET Provider. I am getting the error specified below. The code without the TransactionScope object works -- including when the insert is wrapped in an NHibernate session transaction. Any ideas on what the problem is? BTW, without the EnterpriseServicesInterop, the Informix .NET Provider will not participate in a TransactionScope transaction (verified without NHibernate involved). Code Snippet: public static void TestTScope() { Employee johnp = new Employee { name = "John Prideaux" }; using (TransactionScope tscope = new TransactionScope( TransactionScopeOption.Required, new TransactionOptions() { Timeout = new TimeSpan(0, 1, 0), IsolationLevel = IsolationLevel.ReadCommitted }, EnterpriseServicesInteropOption.Full)) { using (ISession session = OpenSession()) { session.Save(johnp); Console.WriteLine("Saved John to the database"); } } Console.WriteLine("Transaction should be rolled back"); } static ISession OpenSession() { if (factory == null) { Configuration c = new Configuration(); c.AddAssembly(Assembly.GetCallingAssembly()); factory = c.BuildSessionFactory(); } return factory.OpenSession(); } static ISessionFactory factory; Stack Trace: NHibernate.ADOException was unhandled Message="Could not close IBM.Data.Informix.IfxConnection connection" Source="NHibernate" StackTrace: at NHibernate.Connection.ConnectionProvider.CloseConnection(IDbConnection conn) at NHibernate.Connection.DriverConnectionProvider.CloseConnection(IDbConnection conn) at NHibernate.Tool.hbm2ddl.SuppliedConnectionProviderConnectionHelper.Release() at NHibernate.Tool.hbm2ddl.SchemaMetadataUpdater.GetReservedWords(Dialect dialect, IConnectionHelper connectionHelper) at NHibernate.Tool.hbm2ddl.SchemaMetadataUpdater.Update(ISessionFactory sessionFactory) at NHibernate.Impl.SessionFactoryImpl..ctor(Configuration cfg, IMapping mapping, Settings settings, EventListeners listeners) at NHibernate.Cfg.Configuration.BuildSessionFactory() at HelloNHibernate.Employee.OpenSession() in D:\Development\ScratchProject\HelloNHibernate\Employee.cs:line 73 at HelloNHibernate.Employee.TestTScope() in D:\Development\ScratchProject\HelloNHibernate\Employee.cs:line 53 at HelloNHibernate.Program.Main(String[] args) in D:\Development\ScratchProject\HelloNHibernate\Program.cs:line 19 at System.AppDomain._nExecuteAssembly(Assembly assembly, String[] args) at System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String[] args) at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly() at System.Threading.ThreadHelper.ThreadStart_Context(Object state) at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state) at System.Threading.ThreadHelper.ThreadStart() InnerException: IBM.Data.Informix.IfxException Message="ERROR - no error information available" Source="IBM.Data.Informix" ErrorCode=-2147467259 StackTrace: at IBM.Data.Informix.IfxConnection.HandleError(IntPtr hHandle, SQL_HANDLE hType, RETCODE retcode) at IBM.Data.Informix.IfxConnection.DisposeClose() at IBM.Data.Informix.IfxConnection.Close() at NHibernate.Connection.ConnectionProvider.CloseConnection(IDbConnection conn) InnerException:

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• Opened SerialPort crashes C# application

  - by Stefan Teitge

  The computer is connected to measuring device via a physical COM1. I have simple form where I open a serial port, tell the device that I'm alive and occasionally the device sends data. (every some minutes) Thread _readThread = new Thread(Read); SerialPort _serialPort = new SerialPort("COM1", 9600); _serialPort.Parity = Parity.None; _serialPort.DataBits = 8; _serialPort.StopBits = StopBits.One; _serialPort.Handshake = Handshake.None; _serialPort.DtrEnable = true; _serialPort.Open(); _readThread.Start(); _serialPort.Write("#listening"); The read function (which works): public void Read() { string message = _serialPort.ReadLine(); } After approximately one minute the application crashes (even while debugging). It reports an ObjectDisposedException (for the underlying stream?). The message tells that the SafeHandle was closed. Stack strace is below: at Microsoft.Win32.UnsafeNativeMethods.GetOverlappedResult(SafeFileHandle hFile, NativeOverlapped lpOverlapped, Int32& lpNumberOfBytesTransferred, Boolean bWait) at System.IO.Ports.SerialStream.EventLoopRunner.WaitForCommEvent() at System.Threading.ThreadHelper.ThreadStart_Context(Object state) at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state) at System.Threading.ThreadHelper.ThreadStart()* Any ideas? The problem is reported widely but usually involve the device beeing physically detached from the PC.

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