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  • wcf 4.0 service on IIS7

    - by Jan
    I am currently developing a service with wcf 4.0 (visual studio 2010 RC). When I try my service on the Visual Studio Development Server, it all works perfect. However, when I tree to run my service on IIS7 on a windows 7 machine, the service doesn't work anymore. (I already changed the framework version on my application pool). When I call an operation on the service, like the default operation GetData when I create a service, I get an error. I used the WCF test client to connect to the service. When I call the operation on the service, the Visual Studio Just-In-Time debugger shows the following message: An unhandled win32 exception occured in w3wp.exe The Just-In-Time debugger was launched without necessary security permissions. To debug this proces, the JIT debugger must be run as an administrator. Would you like to debug the proces? As far as I know, I am running Visual Studio as an administrator and this is probably the process that starts the JIT debugger. The only option I have is to debug the W3WP process, which is probably not the right thing to do. What can I do the make the Service to run on IIS7?

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  • Assigning a property across threads

    - by Mike
    I have set a property across threads before and I found this post http://stackoverflow.com/questions/142003/cross-thread-operation-not-valid-control-accessed-from-a-thread-other-than-the-t about getting a property. I think my issue with the code below is setting the variable to the collection is an object therefore on the heap and therefore is just creating a pointer to the same object So my question is besides creating a deep copy, or copying the collection into a different List object is there a better way to do the following to aviod the error during the for loop. Cross-thread operation not valid: Control 'lstProcessFiles' accessed from a thread other than the thread it was created on. Code: private void btnRunProcess_Click(object sender, EventArgs e) { richTextBox1.Clear(); BackgroundWorker bg = new BackgroundWorker(); bg.DoWork += new DoWorkEventHandler(bg_DoWork); bg.RunWorkerCompleted += new RunWorkerCompletedEventHandler(bg_RunWorkerCompleted); bg.RunWorkerAsync(lstProcessFiles.SelectedItems); } void bg_DoWork(object sender, DoWorkEventArgs e) { WorkflowEngine engine = new WorkflowEngine(); ListBox.SelectedObjectCollection selectedCollection=null; if (lstProcessFiles.InvokeRequired) { // Try #1 selectedCollection = (ListBox.SelectedObjectCollection) this.Invoke(new GetSelectedItemsDelegate(GetSelectedItems), new object[] { lstProcessFiles }); // Try #2 //lstProcessFiles.Invoke( // new MethodInvoker(delegate { // selectedCollection = lstProcessFiles.SelectedItems; })); } else { selectedCollection = lstProcessFiles.SelectedItems; } // *********Same Error on this line******************** // Cross-thread operation not valid: Control 'lstProcessFiles' accessed // from a thread other than the thread it was created on. foreach (string l in selectedCollection) { if (engine.LoadProcessDocument(String.Format(@"C:\TestDirectory\{0}", l))) { try { engine.Run(); WriteStep(String.Format("Ran {0} Succussfully", l)); } catch { WriteStep(String.Format("{0} Failed", l)); } engine.PrintProcess(); WriteStep(String.Format("Rrinted {0} to debug", l)); } } } private delegate void WriteDelegate(string p); private delegate ListBox.SelectedObjectCollection GetSelectedItemsDelegate(ListBox list); private ListBox.SelectedObjectCollection GetSelectedItems(ListBox list) { return list.SelectedItems; }

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  • CLR Stored Procedures

    - by Paul Hatcherian
    In an ASP.NET application, I have a small number of fairly complex, frequently used operations to execute against a database. In these operations, one or more of several tables needs updates or inserts based a logical evaluation of both input parameters and values of certain tables. I've maintained a separation of logic and data access, so the operation currently looks like this: Request received from client Business layer invokes data layer to retrieve data from database Business layer processes result and determines which operation to execute Business layer invokes appropriate data operation Response sent to client As you can see, the client is kept waiting while two separate requests are made to the database. In searching for a solution to this, I've found CLR Stored Procedures, but I'm not sure if I have the right idea about what they are useful for. I have written a replacement for the code above which especially places steps 2-4 in a CLR SP. My understanding is that the SP will be executed locally by SQL Server and result in only one call being made to the server. My initial benchmark tests show this is actually orders of magnitude slower than my original code, but I attribute that recompilation of the code I have not worked out yet and/or some flaw in my environment. My question is basically, is this the intended use of CLR SPs or am I missing something? I realize this is a bit of a compromise structurally, so if there's a better way to do it I'd love to hear it.

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  • .NET CF -- Set Form height based on InputPanel state

    - by user354941
    Hi, So, I've got a C# project for Windows Mobile phones and I'm trying to work with the InputPanel. Specifically, I've got one form with a stack of Labels and TextBoxes that collect user input. I have an InputPanel that alerts me when the user opens the SIP. Everything works fine so far. When I get messages that the SIP status has changed, I want to change the height of the Form, which doesn't seem possible. Here's my event handler for my InputPanel: void m_InputPanel_EnabledChanged(object sender, EventArgs e) { // :( this assignment operation doesn't work and it doesn't this.ClientSize = inputPanel1.VisibleDesktop.Size; // doesn't work this.Size = inputPanel1.VisibleDesktop.Size; // assignment operation works, but isn't very useful this.visibleHeight = inputPanel1.VisibleDesktop.Height; this.InitializeUI(); } When I say that the assignment operation doesn't work, I mean that the values don't change in the debugger. I can understand that maybe I can't change the size of a Form, but I can't understand why trying to change it wouldn't throw an exception, or give a compiler error. I have my Form WindowState set to Normal instead of Maximized, but it doesn't make a difference. Also, I have read http://www.christec.co.nz/blog/archives/42 this page that tells me how I'm supposed to do this, but I can't easily put all of my controls in a Panel because I'm using a bunch of custom stuff to do alpha background controls.

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  • Appending data to NSFetchedResultsController during find or create loop

    - by Justin Williams
    I have a table view that is managed by an NSFetchedResultsController. I am having an issue with a find-or-create operation, however. When the user hits the bottom of my table view, I am querying my server for another batch of content. If it doesn't exist in the local cache, we create it and store it. If it does exist, however, I want to append that data to the fetched results controller and display it. I can't quite figure that part out. Here's what I'm doing thus far: Passing the returned array of values from my server to an NSOperation to process. In the operation, create a new managed object context to work with. In the operation, I iterate through the array and execute a fetch request to see if the object exists (based on its server id). If the object doesn't exist, we create it and insert it into the operations' managed object context. After the iteration completes, we save the managed object context, which triggers a merge notification on my main thread. At this point, any objects that weren't locally cached in my Core Data store before will appear, but the ones that previously existed do not come along for the ride. I feel like it's something simple I'm missing, and could use a nudge in the right direction.

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  • Making two Windows using CreateWindowsEx() - C

    - by Jamie Keeling
    Hello, I have a windows form that has a simple menu and performs a simple operation, I want to be able to create another windows form with all the functionality of a menu bar, message pump etc.. as a separate thread so I can then share the results of the operation to the second window. I.E. 1) Form A opens Form B opens as a separate thread 2)Form A performs operation 3)Form A passes results via memory to Form B 4)Form B display results I'm confused as to how to go about it, the main app runs fine but i'm not sure how to add a second window if the first one already exists. I think that using CreateWindow will allow me to make another window but again i'm not sure how to access the message pump so I can respond to certain events like WM_CREATE on the second window. I hope it makes sense. Thanks! Edit: I've attempted to make a second window and although this does compile, no windows show atall on build. ////////////////////// // WINDOWS FUNCTION // ////////////////////// LRESULT CALLBACK WindowFunc(HWND hMainWindow, UINT message, WPARAM wParam, LPARAM lParam) { //Fields WCHAR buffer[256]; struct DiceData storage; HWND hwnd; // Act on current message switch(message) { case WM_CREATE: AddMenus(hMainWindow); hwnd = CreateWindowEx( 0, "ChildWClass", (LPCTSTR) NULL, WS_CHILD | WS_BORDER | WS_VISIBLE, 0, 0, 0, 0, hMainWindow, NULL, NULL, NULL); ShowWindow(hwnd, SW_SHOW); break; Any suggestions as to why this happens?

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  • Alright, I'm still stuck on this homework problem. C++

    - by Josh
    Okay, the past few days I have been trying to get some input on my programs. Well I decided to scrap them for the most part and try again. So once again, I'm in need of help. For the first program I'm trying to fix, it needs to show the sum of SEVEN numbers. Well, I'm trying to change is so that I don't need the mem[##] = ####. I just want the user to be able to input the numbers and the program run from there and go through my switch loop. And have some kind of display..saying like the sum is?.. Here's my code so far. #include <iostream> #include <iomanip> #include <ios> using namespace std; int main() { const int READ = 10; const int WRITE = 11; const int LOAD = 20; const int STORE = 21; const int ADD = 30; const int SUBTRACT = 31; const int DIVIDE = 32; const int MULTIPLY = 33; const int BRANCH = 40; const int BRANCHNEG = 41; const int BRANCHZERO = 42; const int HALT = 43; int mem[100] = {0}; //Making it 100, since simpletron contains a 100 word mem. int operation; //taking the rest of these variables straight out of the book seeing as how they were italisized. int operand; int accum = 0; // the special register is starting at 0 int counter; for ( counter=0; counter < 100; counter++) mem[counter] = 0; // This is for part a, it will take in positive variables in //a sent-controlled loop and compute + print their sum. Variables from example in text. mem[0] = 1009; mem[1] = 1109; mem[2] = 2010; mem[3] = 2111; mem[4] = 2011; mem[5] = 3100; mem[6] = 2113; mem[7] = 1113; mem[8] = 4300; counter = 0; //Makes the variable counter start at 0. while(true) { operand = mem[ counter ]%100; // Finds the op codes from the limit on the mem (100) operation = mem[ counter ]/100; //using a switch loop to set up the loops for the cases switch ( operation ){ case READ: //reads a variable into a word from loc. Enter in -1 to exit cout <<"\n Input a positive variable: "; cin >> mem[ operand ]; counter++; break; case WRITE: // takes a word from location cout << "\n\nThe content at location " << operand << " is " << mem[operand]; counter++; break; case LOAD:// loads accum = mem[ operand ];counter++; break; case STORE: //stores mem[ operand ] = accum;counter++; break; case ADD: //adds accum += mem[operand];counter++; break; case SUBTRACT: // subtracts accum-= mem[ operand ];counter++; break; case DIVIDE: //divides accum /=(mem[ operand ]);counter++; break; case MULTIPLY: // multiplies accum*= mem [ operand ];counter++; break; case BRANCH: // Branches to location counter = operand; break; case BRANCHNEG: //branches if acc. is < 0 if (accum < 0) counter = operand; else counter++; break; case BRANCHZERO: //branches if acc = 0 if (accum == 0) counter = operand; else counter++; break; case HALT: // Program ends break; } } return 0; } part B int main() { const int READ = 10; const int WRITE = 11; const int LOAD = 20; const int STORE = 21; const int ADD = 30; const int SUBTRACT = 31; const int DIVIDE = 32; const int MULTIPLY = 33; const int BRANCH = 40; const int BRANCHNEG = 41; const int BRANCHZERO = 41; const int HALT = 43; int mem[100] = {0}; int operation; int operand; int accum = 0; int pos = 0; int j; mem[22] = 7; // loop 7 times mem[25] = 1; // increment by 1 mem[00] = 4306; mem[01] = 2303; mem[02] = 3402; mem[03] = 6410; mem[04] = 3412; mem[05] = 2111; mem[06] = 2002; mem[07] = 2312; mem[08] = 4210; mem[09] = 2109; mem[10] = 4001; mem[11] = 2015; mem[12] = 3212; mem[13] = 2116; mem[14] = 1101; mem[15] = 1116; mem[16] = 4300; j = 0; while ( true ) { operand = memory[ j ]%100; // Finds the op codes from the limit on the memory (100) operation = memory[ j ]/100; //using a switch loop to set up the loops for the cases switch ( operation ){ case 1: //reads a variable into a word from loc. Enter in -1 to exit cout <<"\n enter #: "; cin >> memory[ operand ]; break; case 2: // takes a word from location cout << "\n\nThe content at location " << operand << "is " << memory[operand]; break; case 3:// loads accum = memory[ operand ]; break; case 4: //stores memory[ operand ] = accum; break; case 5: //adds accum += mem[operand];; break; case 6: // subtracts accum-= memory[ operand ]; break; case 7: //divides accum /=(memory[ operand ]); break; case 8: // multiplies accum*= memory [ operand ]; break; case 9: // Branches to location j = operand; break; case 10: //branches if acc. is < 0 break; case 11: //branches if acc = 0 if (accum == 0) j = operand; break; case 12: // Program ends exit(0); break; } j++; } return 0; }

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  • is mysql index useful on column 'state' when only doing bit-operations on the column?

    - by Geert-Jan
    I have a lot of domain entities (stored in mysql) which undergo lots of different operations. Each operation is executed from a different program. I need to keep (flow)-state for these entities which I implemented in as a long field 'flowstate' used as a bitset. to query mysql for entities which have undergone a certain operation I do something like: select * from entities where state >> 7 & 1 = 1 Indicating bit 7 (cooresponding to operation 7) has run. (<-- simplified) Anyway, I really didn't pay attention to the performance implications of this setup in the beginning, and I think I'm in a bit of trouble since queries as the above run pretty slow. What I'd like to know: Does an mysql index on 'flowstate' help at all? After all it's not a single value Mysql can quickly find using a binary sort or whatever. If it doesn't, are there any other things I could do to speed things up? . Are there special 'mask-indices' for fields with use-cases as the above? TIA, Geert-jan

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  • Summary row count appears zero for a field like 'wip.aggregatedValue' but not for 'wip'

    - by Tushar Khairnar
    Hi, I am using advanceddatagrid with groupedColumns and summary rows. I have following columns grop. <mx:AdvancedDataGridColumn id="wipId" dataField="wip.aggregatedValue" headerText="WIP"/> <mx:AdvancedDataGridColumn id="closedId" dataField="closed.aggregatedValue"/> <mx:AdvancedDataGridColumn dataField="newevents"/> </mx:AdvancedDataGridColumnGroup> <mx:SummaryRow summaryPlacement="group"> <mx:fields> <mx:SummaryField operation="SUM" dataField="wip.aggregatedValue" /> </mx:fields> </mx:SummaryRow> <mx:SummaryRow summaryPlacement="group"> <mx:fields> <mx:SummaryField operation="SUM" dataField="closed.aggregatedValue" /> </mx:fields> </mx:SummaryRow> <mx:SummaryRow summaryPlacement="group"> <mx:fields> <mx:SummaryField operation="SUM" dataField="newevents" /> </mx:fields> </mx:SummaryRow> So for fields WIP and closedEvents summary row appears zero but for newevents it appears correctly. Please let me know how to solve this problem. Thanks tushar

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  • Handling data update/freshness issue in web-app in general (or GWT specifically)

    - by edwin.nathaniel
    In general, how do you guys handle user update/data freshness interaction with the user (UI issue) in web-apps? For example: Multi-users web-app (like project management) Login to a "virtual" space People can update project names, etc How to handle a situation such that: user-A and user-B load a project with title "Project StackOverflow" user-B updates the title to "Project StackExchange" user-A updates the title after user-B update operation to "Project Basecamp" The question I'm asking is from the user perspective (UI) and not about transactional operation. What do most people do in this situation? What would you do after user-B updates the title in user-A screen/view? What happened when user-A tries to update the title after user-B finished his/her update operation? do you inform user-A that the title has changed and he/she has to reload the page? do you go ahead and change the title and let user-B has old data? Do you do some sort of application-level "locking" mechanism? (if someone is updating, nobody else can?) Or fix the application workflow? (who has the access to be able to change things, etc). What would be the simplest solution, but at the same time not annoy the user with more dialog/warning messages. I've encountered this particular problem frequently in a GWT app specifically where domain models are being passed around and refreshing the whole app/client-side isn't the optimal solution in my mind (since it means the whole "loading"/initialization phase must be executed again in this specific environment). Maybe the answer is to stay away from GWT? :) Love to hear options, solutions, and advises from you guys. Thanks

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  • JDBC transaction dead-lock solution required?

    - by user49767
    It's a scenario described my friend and challenged to find solution. He is using Oracle database and JDBC connection with read committed as transaction isolation level. In one of the transaction, he updates a record and executes selects statement and commits the transaction. when everything happening within single thread, things are fine. But when multiple requests are handled, dead-lock happens. Thread-A updates a record. Thread B updates another record. Thread-A issues select statement and waits for Thread-B's transaction to complete the commit operation. Thread-B issues select statement and waits for Thread-A's transaction to complete the commit operation. Now above causes dead-lock. Since they use command pattern, the base framework allows to issue commit only once (at the end of all the db operation), so they are unable to issue commit immediately after select statement. My argument was Thread-A supposed to select all the records which are committed and hence should not be issue. But he said that Thread-A will surely wait till Thread-B commits the record. is that true? What are all the ways, to avoid the above issue? is it possible to change isolation-level? (without changing underlying java framework) Little information about base framework, it is something similar to Struts action, their each and every request handled by one action, transaction begins before execution and commits after execution.

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  • There was no endpoint listening at net.pipe://localhost/...

    - by virsum
    I have two WCF services hosted in a single Windows Service on a Windows Server 2003 machine. If the Windows service needs to access either of the WCF services (like when a timed event occurs), it uses one of the five named pipe endpoints exposed (different service contracts). The service also exposes HTTP MetadataExchange endpoints for each of the two services, and net.tcp endpoints for consumers external to the server. Usually things work great, but every once in a while I get an error message that looks something like this: System.ServiceModel.EndpointNotFoundException: There was no endpoint listening at net.pipe://localhost/IPDailyProcessing that could accept the message. This is often caused by an incorrect address or SOAP action. See InnerException, if present, for more details. --- System.IO.PipeException: The pipe endpoint 'net.pipe://localhost/IPDailyProcessing' could not be found on your local machine. --- End of inner exception stack trace --- Server stack trace: at System.ServiceModel.Channels.PipeConnectionInitiator.GetPipeName(Uri uri) at System.ServiceModel.Channels.NamedPipeConnectionPoolRegistry.NamedPipeConnectionPool.GetPoolKey(EndpointAddress address, Uri via) at System.ServiceModel.Channels.ConnectionPoolHelper.EstablishConnection(TimeSpan timeout) at System.ServiceModel.Channels.ClientFramingDuplexSessionChannel.OnOpen(TimeSpan timeout) at System.ServiceModel.Channels.CommunicationObject.Open(TimeSpan timeout) at System.ServiceModel.Channels.ServiceChannel.OnOpen(TimeSpan timeout) at System.ServiceModel.Channels.CommunicationObject.Open(TimeSpan timeout) at System.ServiceModel.Channels.ServiceChannel.CallOpenOnce.System.ServiceModel.Channels.ServiceChannel.ICallOnce.Call(ServiceChannel channel, TimeSpan timeout) at System.ServiceModel.Channels.ServiceChannel.CallOnceManager.CallOnce(TimeSpan timeout, CallOnceManager cascade) at System.ServiceModel.Channels.ServiceChannel.EnsureOpened(TimeSpan timeout) at System.ServiceModel.Channels.ServiceChannel.Call(String action, Boolean oneway, ProxyOperationRuntime operation, Object[] ins, Object[] outs, TimeSpan timeout) at System.ServiceModel.Channels.ServiceChannel.Call(String action, Boolean oneway, ProxyOperationRuntime operation, Object[] ins, Object[] outs) at System.ServiceModel.Channels.ServiceChannelProxy.InvokeService(IMethodCallMessage methodCall, ProxyOperationRuntime operation) at System.ServiceModel.Channels.ServiceChannelProxy.Invoke(IMessage message) It doesn't happen reliably, which is maddening because I can't repeat it when I want to. In my windows service I also have some timed events and some file listeners, but these are fairly infrequent events. Does anyone have any ideas why I might be encountering an issue? Any help would be greatly appreciated.

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  • Use date operations on a computed field filter in a view

    - by stephenhay
    I'd like to expose a filter in Views based on a Computed Field. This field should utilize the date operation "less than". Apparently, a date type is not available to computed field (varchar is). However, using varchar results in views treating the field as a string rather than as a date, without the operation I'm looking for. So I tried using a timestamp instead of a date, which allowed me to use an integer data type. The exposed view gives me a "less than" operation, but as it's still not a date, the user must type in a timestamp. Not handy. So I'm thinking the best way to do this is to create a new (hidden) CCK field which is a date field, and set the value of this field to the value of the Computed Field. I can then use the new CCK field for my exposed filter. But I'm not getting anywhere with this, as I'm unsure how to set another CCK field with a Computed Field. To return the value to the computed field itself, I'm using the standard: $node_field[0]['value'] = $newestdate; I would like to set the value of the new CCK field to $newestdate as well. Can anyone help?

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  • How can I intercept an exception occurred during serialization in WCF?

    - by bonomo
    I have a legit data object with all data contract / data member attributes. For some reason the WCF service crashes after the operation has completed and the result is passed as a return value. I believe it has something to do with WCF not being able to serialize that result properly. The test client doesn't say anything specific: The underlying connection was closed: The connection was closed unexpectedly. Server stack trace: at System.ServiceModel.Channels.HttpChannelUtilities.ProcessGetResponseWebException(WebException webException, HttpWebRequest request, HttpAbortReason abortReason) at System.ServiceModel.Channels.HttpChannelFactory.HttpRequestChannel.HttpChannelRequest.WaitForReply(TimeSpan timeout) at System.ServiceModel.Channels.RequestChannel.Request(Message message, TimeSpan timeout) at System.ServiceModel.Dispatcher.RequestChannelBinder.Request(Message message, TimeSpan timeout) at System.ServiceModel.Channels.ServiceChannel.Call(String action, Boolean oneway, ProxyOperationRuntime operation, Object[] ins, Object[] outs, TimeSpan timeout) at System.ServiceModel.Channels.ServiceChannelProxy.InvokeService(IMethodCallMessage methodCall, ProxyOperationRuntime operation) at System.ServiceModel.Channels.ServiceChannelProxy.Invoke(IMessage message) Exception rethrown at [0]: at System.Runtime.Remoting.Proxies.RealProxy.HandleReturnMessage(IMessage reqMsg, IMessage retMsg) at System.Runtime.Remoting.Proxies.RealProxy.PrivateInvoke(MessageData& msgData, Int32 type) at IFacade.PickSecurities(String pattern, Int32 atMost) at FacadeClient.PickSecurities(String pattern, Int32 atMost) Inner Exception: The underlying connection was closed: The connection was closed unexpectedly. at System.Net.HttpWebRequest.GetResponse() at System.ServiceModel.Channels.HttpChannelFactory.HttpRequestChannel.HttpChannelRequest.WaitForReply(TimeSpan timeout) I am in control of creating the instance of the service using a customized service host factory. I know I can set up trace listeners and check the logs, but it's a lot of hassle to do. So I would rather handle it explicitly on the server at the time it happens. So I how can I intercept that exception programmatically and return an appropriate fault meassage?

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  • WCF - "Encountered unexpected character 'c'."

    - by Villager
    Hello, I am trying to do something that I thought would be simple. I need to create a WCF service that I can post to via JQuery. I have an operation in my WCF service that is defined as follows: [OperationContract] [WebInvoke(Method = "POST", BodyStyle = WebMessageBodyStyle.WrappedRequest, RequestFormat=WebMessageFormat.Json, ResponseFormat=WebMessageFormat.Json)] public string SendMessage(string message, int urgency) { try { // Do stuff return "1"; // 1 represents success } catch (Exception) { return "0"; } } I then try to access this operation from an ASP.NET page via JQuery. My JQuery code to access this operation looks like the following: function sendMessage(message) { $.ajax({ url: "/resources/services/myService.svc/SendMessage", type: "POST", contentType: "application/json; charset=utf-8", data: ({ message: message, urgency: '1' }), dataType: "json", success: function (data) { alert("here!"); }, error: function (req, msg, obj) { alert("error: " + req.responseText); } }); } When I execute this script, the error handler is tripped. In it, I receive an error that says: "Encountered unexpected character 'c'." This message is included with a long stack trace. My question is, what am I doing wrong? I have received other posts such as this one (http://stackoverflow.com/questions/320291/how-to-post-an-array-of-complex-objects-with-json-jquery-to-asp-net-mvc-controll) without any luck. How do I get this basic interaction working? Thank you!

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  • What happens when we say "listen to a port" ?

    - by smwikipedia
    Hi, When we start a server application, we always need to speicify the port number it listens to. But how is this "listening mechanism" implemented under the hood? My current imagination is like this: The operating system associate the port number with some buffer. The server application's responsibiligy is to monitor this buffer. If there's no data in this buffer, the server application's listen operation will just block the application. When some data arrives from the wire, the operating system will know that check the data and see if it is targed at this port number. And then it will fill the buffer. And then OS will notify the blocked server application and the server application will get the data and continue to run. Question is: If the above scenario is correct, how could the opearting system know there's data arriving from wire? It cannot be a busy pooling. Is it some kind of interrupt-based mechanism? If there's too much data arriving and the buffer is not big enough, will there be data loss? Is the "listen to a port" operation really a blocking operation? Many thanks.

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  • Replace without the replace function

    - by Molly Potter
    Assignment: Let X and Y be two words. Find/Replace is a common word processing operation that finds each occurrence of word X and replaces it with word Y in a given document. Your task is to write a program that performs the Find/Replace operation. Your program will prompt the user for the word to be replaced (X), then the substitute word (Y ). Assume that the input document is named input.txt. You must write the result of this Find/Replace operation to a file named output.txt. Lastly, you cannot use the replace() string function built into Python (it would make the assignment much too easy). To test your code, you should modify input.txt using a text editor such as Notepad or IDLE to contain different lines of text. Again, the output of your code must look exactly like the sample output. This is my code: input_data = open('input.txt','r') #this opens the file to read it. output_data = open('output.txt','w') #this opens a file to write to. userStr= (raw_input('Enter the word to be replaced:')) #this prompts the user for a word userReplace =(raw_input('What should I replace all occurences of ' + userStr + ' with?')) #this prompts the user for the replacement word for line in input_data: words = line.split() if userStr in words: output_data.write(line + userReplace) else: output_data.write(line) print 'All occurences of '+userStr+' in input.txt have been replaced by '+userReplace+' in output.txt' #this tells the user that we have replaced the words they gave us input_data.close() #this closes the documents we opened before output_data.close() It won't replace anything in the output file. Help!

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  • Making two Windows using CreateWindowsEx()

    - by Jamie Keeling
    Hello, I have a windows form that has a simple menu and performs a simple operation, I want to be able to create another windows form with all the functionality of a menu bar, message pump etc.. as a separate thread so I can then share the results of the operation to the second window. I.E. 1) Form A opens Form B opens as a separate thread 2)Form A performs operation 3)Form A passes results via memory to Form B 4)Form B display results I'm confused as to how to go about it, the main app runs fine but i'm not sure how to add a second window if the first one already exists. I think that using CreateWindow will allow me to make another window but again i'm not sure how to access the message pump so I can respond to certain events like WM_CREATE on the second window. I hope it makes sense. Thanks! Edit: I've attempted to make a second window and although this does compile, no windows show atall on build. ////////////////////// // WINDOWS FUNCTION // ////////////////////// LRESULT CALLBACK WindowFunc(HWND hMainWindow, UINT message, WPARAM wParam, LPARAM lParam) { //Fields WCHAR buffer[256]; struct DiceData storage; HWND hwnd; // Act on current message switch(message) { case WM_CREATE: AddMenus(hMainWindow); hwnd = CreateWindowEx( 0, "ChildWClass", (LPCTSTR) NULL, WS_CHILD | WS_BORDER | WS_VISIBLE, 0, 0, 0, 0, hMainWindow, NULL, NULL, NULL); ShowWindow(hwnd, SW_SHOW); break; Any suggestions as to why this happens?

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  • How to effectively execute this cron job?

    - by Lost_in_code
    I have a table with 200 rows. I'm running a cron job every 10 minutes to perform some kind of insert/update operation on the table. The operation needs to be performed only on 5 rows at a time every time the cron job runs. So in first 10 mins records 1-5 are updated, records 5-10 in the 20th minute and so on. When the cron job runs for the 20th time, all the records in the table would have been updated exactly once. This is what is to be achieved at least. And the next cron job should repeat the process again. The problem: is that, every time a cron job runs, the insert/update operation should be performed on N rows (not just 5 rows). So, if N is 100, all records would've been updated by just 2 cron jobs. And the next cron job would repeat the process again. Here's an example: This is the table I currently have (200 records). Every time a cron job executes, it needs to pick N records (which I set as a variable in PHP) and update the time_md5 field with the current time's MD5 value. +---------+-------------------------------------+ | id | time_md5 | +---------+-------------------------------------+ | 10 | 971324428e62dd6832a2778582559977 | | 72 | 1bd58291594543a8cc239d99843a846c | | 3 | 9300278bc5f114a290f6ed917ee93736 | | 40 | 915bf1c5a1f13404add6612ec452e644 | | 599 | 799671e31d5350ff405c8016a38c74eb | | 56 | 56302bb119f1d03db3c9093caf98c735 | | 798 | 47889aa559636b5512436776afd6ba56 | | 8 | 85fdc72d3b51f0b8b356eceac710df14 | | .. | ....... | | .. | ....... | | .. | ....... | | .. | ....... | | 340 | 9217eab5adcc47b365b2e00bbdcc011a | <-- 200th record +---------+-------------------------------------+ So, the first record(id 10) should not be updated more than once, till all 200 records are updated once - the process should start over once all the records are updated once. I have some idea on how this could be achieved, but I'm sure there are more efficient ways of doing it. Any suggestions?

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  • Time gaps between host clEnqueue_xxx calls

    - by dialer
    Consider these OpenCL calls (3 memcpy DtoH, 4313 cl_float elements each): clEnqueueReadBuffer(CommandQueue, SpectrumAbsMem, CL_FALSE, 0, SpectrumMemSize, SpectrumAbs, 0, NULL, NULL); clEnqueueReadBuffer(CommandQueue, SpectrumReMem, CL_FALSE, 0, SpectrumMemSize, SpectrumRe, 0, NULL, NULL); clEnqueueReadBuffer(CommandQueue, SpectrumImMem, CL_FALSE, 0, SpectrumMemSize, SpectrumIm, 0, NULL, NULL); When I analyze these with the NVIDIA visual profiler, I see that the actual memcpy operation only takes 8 us, but there is a significant gap of around 130 us after each memcpy. I'm already using the supposedly asynchronous method (the CL_FALSE in the argument list). When I use only one operation, but with three times the size, the operation is way faster. Why is the time gap between the actual memcpy operations so huge, whereas the gap between the kernel execution (exactly before these three operations) and the first memcpy is only 7us? Can I get rid of it, or do I need to accumulate more data before starting a memcpy? If so, is there a convenient way how I could combine mutliple arrays into a single contiguous block of memory, but still have a cl_mem object as a separate device memory pointer to each section?

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  • Locking database edit by key name

    - by Will Glass
    I need to prevent simultaneous edits to a database field. Users are executing a push operation on a structured data field, so I want to sequence the operations, not simply ignore one edit and take the second. Essentially I want to do synchronized(key name) { push value onto the database field } and set up the synchronized item so that only one operation on "key name" will occur at a time. (note: I'm simplifying, it's not always a simple push). A crude way to do this would be a global synchronization, but that bottlenecks the entire app. All I need to do is sequence two simultaneous writes with the same key, which is rare but annoying occurrence. This is a web-based java app, written with Spring (and using JPA/MySQL). The operation is triggered by a user web service call. (the root cause is when a user sends two simultaneous http requests with the same key). I've glanced through the Doug Lea/Josh Bloch/et al Concurrency in Action, but don't see an obvious solution. Still, this seems simple enough I feel there must be an elegant way to do this.

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  • Client Server communication in Java - which approach to use?

    - by markovuksanovic
    I have a typical client server communication - Client sends data to the server, server processes that, and returns data to the client. The problem is that the process operation can take quite some time - order of magnitude - minutes. There are a few approaches that could be used to solve this. Establish a connection, and keep it alive, until the operation is finished and the client receives the response. Establish connection, send data, close the connection. Now the processing takes place and once it is finished the server could establish a connection to the client to send the data. Establish a connection, send data, close the connection. Processing takes place. client asks server, every n minutes/seconds if the operation is finished. If the processing is finished the client fetches the data. I was wondering which approach would be the best way to use. Is there maybe some "de facto" standard for solving this problem? How "expensive" is opening a socket in Java? Solution 1. seems pretty nasty to me, but 2. and 3. could do. The problem with solution 2. is that the server needs to know on which port the client is listening, while solution 3. adds some network overhead.

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  • What would happen if a same file being read and appended at the same time(python programming)?

    - by Shane
    I'm writing a script using two separate thread one doing file reading operation and the other doing appending, both threads run fairly frequently. My question is, if one thread happens to read the file while the other is just in the middle of appending strings such as "This is a test" into this file, what would happen? I know if you are appending a smaller-than-buffer string, no matter how frequently you read the file in other threads, there would never be incomplete line such as "This i" appearing in your read file, I mean the os would either do: append "This is a test" - read info from the file; or: read info from the file - append "This is a test" to the file; and such would never happen: append "This i" - read info from the file - append "s a test". But if "This is a test" is big enough(assuming it's a bigger-than-buffer string), the os can't do appending job in one operation, so the appending job would be divided into two: first append "This i" to the file, then append "s a test", so in this kind of situation if I happen to read the file in the middle of the whole appending operation, would I get such result: append "This i" - read info from the file - append "s a test", which means I might read a file that includes an incomplete string?

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  • Externally disabling signals for a Linux program.

    - by Harry
    Hello, On Linux, is it possible to somehow disable signaling for programs externally... that is, without modifying their source code? Context: I'm calling a C (and also a Java) program from within a bash script on Linux. I don't want any interruptions for my bash script, and for the other programs that the script launches (as foreground processes). While I can use a... trap '' INT ... in my bash script to disable the Ctrl C signal, this works only when the program control happens to be in the bash code. That is, if I press Ctrl C while the C program is running, the C program gets interrupted and it exits! This C program is doing some critical operation because of which I don't want it be interrupted. I don't have access to the source code of this C program, so signal handling inside the C program is out of question. #!/bin/bash trap 'echo You pressed Ctrl C' INT # A C program to emulate a real-world, long-running program, # which I don't want to be interrupted, and for which I # don't have the source code! # # File: y.c # To build: gcc -o y y.c # # #include <stdio.h> # int main(int argc, char *argv[]) { # printf("Performing a critical operation...\n"); # for(;;); // Do nothing forever. # printf("Performing a critical operation... done.\n"); # } ./y Regards, /HS

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  • Array Assignment

    - by Mahesh
    Let me explain with an example - #include <iostream> void foo( int a[2], int b[2] ) // I understand that, compiler doesn't bother about the // array index and converts them to int *a, int *b { a = b ; // At this point, how ever assignment operation is valid. } int main() { int a[] = { 1,2 }; int b[] = { 3,4 }; foo( a, b ); a = b; // Why is this invalid here. return 0; } Is it because, array decays to a pointer when passed to a function foo(..), assignment operation is possible. And in main, is it because they are of type int[] which invalidates the assignment operation. Doesn't a,b in both the cases mean the same ? Thanks. Edit 1: When I do it in a function foo, it's assigning the b's starting element location to a. So, thinking in terms of it, what made the language developers not do the same in main(). Want to know the reason.

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