Search Results

Search found 5172 results on 207 pages for 'stackoverflow podcast'.

Page 162/207 | < Previous Page | 158 159 160 161 162 163 164 165 166 167 168 169  | Next Page >

• How to correctly set the ORACLE_HOME variable on Ubuntu 9.x?

  - by nowarninglabel

  I have the same problem as listed here: http://stackoverflow.com/questions/52239/oracle-lost-sysdba-password although I did not lose the password, I entered it twice in the configure script originally, and then when I went to login (localhost:8080/apex, password not accepted. I don't have anything in the database, I just want to install and use Oracle-XE. I have tried apt-get removing it twice and reinstalling, but if I try to run /etc/init.d/oracle-xe configure again and I get "Oracle Database 10g Express Edition is already configured" despite the second time removing any folders I could find for Oracle XE. I tried running sqlplus "/ as sysdba" but all I get is: "Error 6 initializing SQL*Plus Message file sp1.msb not found SP2-0750: You may need to set ORACLE_HOME to your Oracle software directory" I tried setting the variable via export. (also tried set). Tried: "export ORACLE_HOME=/usr/lib/oracle/xe/app/oracle/product/10.2.0/server/bin/sqlplus" and all the subdirectories of that. Same error every time. What is the ORACLE_HOME supposed to be set to? The only reference I have seen either just say general or say the above up to the version number then "/db_1". I do no thave a db_1. Let me know if need any clarification. Don't understand what I did wrong in this process.

  Read the article

• EAV Database Sheme

  - by GLO

  Hello Stackoverflow comunity! I believe that my question has to do with all db guru here! Do you know the EAV DB Scheme ( http://en.wikipedia.org/wiki/Entity-attribute-value_model ) and what they say about the performing of this model. I wonder, If I break this model into smaller tables what the result is? Let's talk about it. I have a db with more that 100K records. A lot of categories and many items ( with different properties per category ) Everything is stored in a EAV. If I try to break this scheme and create for any category a unique table is something that will I have to avoid? Yes, I know that probably I'll have a lot of tables and I'll need to ALTER them if I want to add an extra field, BUT is this so wrong? I have also read that as many tables I have, the db will be populate with more files and this isn't good for any filesystem. Any suggestion? Thank you!

  Read the article

• Joining on a common table, how do you get a FULL OUTER JOIN to expand on another table?

  - by stimpy77

  I've scoured StackOverflow and Google for an answer to this problem. I'm trying to create a Microsot SQL Server 2008 view. Not a stored procedure. Not a function. Just a query (i.e. a view). I have three tables. The first table defines a common key, let's say "CompanyID". The other two tables have a sometimes-common field, let's say "EmployeeName". I want a single table result that, when my WHERE clause says "WHERE CompanyID = 12" looks like this: CompanyID | TableA | TableB 12 | John Doe | John Doe 12 | Betty Sue | NULL 12 | NULL | Billy Bob I've tried a FULL OUTER JOIN that looks like this: SELECT Company.CompanyID, TableA.EmployeeName, TableB.EmployeeName FROM Company FULL OUTER JOIN TableA ON Company.CompanyID = TableA.CompanyID FULL OUTER JOIN TableB ON Company.CompanyID = TableB.CompanyID AND (TableA.EmployeeName IS NULL OR TableB.EmployeeName IS NULL OR TableB.EmployeeName = TableA.EmployeeName) I'm only getting the NULL from one matched table, I'm not getting the expansion for the other table. In the above sample, I'm basically only getting the first and third rows and not the second. Can someone help me create this query and show me how this is done correctly? BTW I already have a stored procedure that looks very clean and populates an in-memory table, but that isn't what I want. Thanks.

  Read the article

• Non-Relational Database Design

  - by Ian Varley

  I'm interested in hearing about design strategies you have used with non-relational "nosql" databases - that is, the (mostly new) class of data stores that don't use traditional relational design or SQL (such as Hypertable, CouchDB, SimpleDB, Google App Engine datastore, Voldemort, Cassandra, SQL Data Services, etc.). They're also often referred to as "key/value stores", and at base they act like giant distributed persistent hash tables. Specifically, I want to learn about the differences in conceptual data design with these new databases. What's easier, what's harder, what can't be done at all? Have you come up with alternate designs that work much better in the non-relational world? Have you hit your head against anything that seems impossible? Have you bridged the gap with any design patterns, e.g. to translate from one to the other? Do you even do explicit data models at all now (e.g. in UML) or have you chucked them entirely in favor of semi-structured / document-oriented data blobs? Do you miss any of the major extra services that RDBMSes provide, like relational integrity, arbitrarily complex transaction support, triggers, etc? I come from a SQL relational DB background, so normalization is in my blood. That said, I get the advantages of non-relational databases for simplicity and scaling, and my gut tells me that there has to be a richer overlap of design capabilities. What have you done? FYI, there have been StackOverflow discussions on similar topics here: the next generation of databases changing schemas to work with Google App Engine choosing a document-oriented database

  Read the article

• Can't get past "A potentially dangerous Request.Form value was detected..." error

  - by joshb

  I'm doing my first ASP.NET MVC2 project and I can't get past the "A potentially dangerous Request.Form value was detected..." error when trying to submit a form. I've done this in MVC1 using the ValidateInputAttribute and I've read about the breaking change in .NET 4 that requires setting the request validation mode in the web.config. Basically I'm doing exactly what is outlined in this thread: http://stackoverflow.com/questions/2019843/a-potentially-dangerous-request-form-value-in-mvc-2-asp-net-4-0. Nothing's working though so I must be missing something. Here's my code: Web.config <configuration> <system.web> <httpHandlers> <add path="*" verb="*" type="System.Web.HttpNotFoundHandler"/> </httpHandlers> <httpRuntime requestValidationMode="2.0" /> <pages validateRequest="true" pageParserFilterType="System.Web.Mvc.ViewTypeParserFilter, System.Web.Mvc, Version=2.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" pageBaseType="System.Web.Mvc.ViewPage, System.Web.Mvc, Version=2.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" userControlBaseType="System.Web.Mvc.ViewUserControl, System.Web.Mvc, Version=2.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"> <controls> <add assembly="System.Web.Mvc, Version=2.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" namespace="System.Web.Mvc" tagPrefix="mvc" /> </controls> </pages> </system.web> <system.webServer> <validation validateIntegratedModeConfiguration="false" /> <handlers> <remove name="BlockViewHandler"/> <add name="BlockViewHandler" path="*" verb="*" preCondition="integratedMode" type="System.Web.HttpNotFoundHandler" /> </handlers> </system.webServer> </configuration> Controller action [AcceptVerbs(HttpVerbs.Post)] [ValidateInput(false)] public ActionResult Edit(Page pageToEdit) { // do stuff.... } Any ideas on what I'm doing wrong here?

  Read the article

• Java: does the EDT restart or not when an exception is thrown?

  - by NoozNooz42

  (the example code below is self-contained and runnable, you can try it, it won't crash your system :) Tom Hawtin commented on the question here: http://stackoverflow.com/questions/3018165 that: It's unlikely that the EDT would crash. Unchecked exceptions thrown in EDT dispatch are caught, dumped and the thread goes on. Can someone explain me what is going on here (every time you click on the "throw an unchecked exception" button, a divide by zero is performed, on purpose): import javax.swing.*; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import java.awt.event.WindowAdapter; import java.awt.event.WindowEvent; public class CrashEDT extends JFrame { public static void main(String[] args) { final CrashEDT frame = new CrashEDT(); frame.addWindowListener(new WindowAdapter() { public void windowClosing( WindowEvent e) { System.exit(0); } }); final JButton jb = new JButton( "throw an unchecked exception" ); jb.addActionListener( new ActionListener() { public void actionPerformed( ActionEvent e ) { System.out.println( "Thread ID:" + Thread.currentThread().getId() ); System.out.println( 0 / Math.abs(0) ); } } ); frame.add( jb ); frame.setSize(300, 150); frame.setVisible(true); } } I get the following message (which is what I'd expect): Exception in thread "AWT-EventQueue-0" java.lang.ArithmeticException: / by zero and to me this is an unchecked exception right? You can see that the thread ID is getting incremented every time you trigger the crash. So is the EDT automatically restarted every time an unchecked exception is thrown or are unchecked exceptions "caught, dumped and the thread goes on" like Tom Hawtin commented? What is going on here?

  Read the article

• Why does my REST request return garbage data?

  - by Alienfluid

  I am trying to use LWP::Simple to make a GET request to a REST service. Here's the simple code: use LWP::Simple; $uri = "http://api.stackoverflow.com/0.8/questions/tagged/php"; $jsonresponse= get $uri; print $jsonresponse; On my local machine, running Ubuntu 10.4, and Perl version 5.10.1: farhan@farhan-lnx:~$ perl --version This is perl, v5.10.1 (*) built for x86_64-linux-gnu-thread-multi I can get the correct response and have it printed on the screen. E.g.: farhan@farhan-lnx:~$ head -10 output.txt { "total": 1000, "page": 1, "pagesize": 30, "questions": [ { "tags": [ "php", "arrays", "coding-style" (... snipped ...) But on my host's machine to which I SSH into, I get garbage printed on the screen for the same exact code. I am assuming it has something to do with the encoding, but the REST service does not return the character set type in the response, so how do I force LWP::Simple to use the correct encoding? Any ideas what may be going on here? Here's the version of Perl on my host's machine: [dredd]$ perl --version This is perl, v5.8.8 built for x86_64-linux-gnu-thread-multi

  Read the article

• Flex: Double click event propagation on datagrid dependent on component order?

  - by MyMacAndMe

  I'd like to have a double click event on a datagrid in Flex3. The following example only works if the Accordion (id = "mustBeSecond") container comes after the DataGrid. Why is the order of the components important and what can I do to prevent this behavior? (The example does not work. If you change the order of "mustBeSecond" and "gridReportConversions" the example works fine) <mx:Script> <![CDATA[ import mx.controls.Alert; import mx.collections.ArrayCollection; [Bindable] private var dp:ArrayCollection = new ArrayCollection([ {qty:1,referer:'http://google.com'}, {qty:25,referer:'http://cnn.com'}, {qty:4,referer:'http:stackoverflow.com'}]); private function refererRowDoubleClicked(e:Event):void { Alert.show("double click"); } ]]> </mx:Script> <mx:HBox width="100%" height="100%"> <mx:Accordion width="200" height="200" id="mustBeSecond"> <mx:Canvas label="Navigation Box" width="100%" height="100%"> <mx:VBox> <mx:LinkButton label="First Link" /> <mx:LinkButton label="Second Link" /> </mx:VBox> </mx:Canvas> </mx:Accordion> <mx:DataGrid id="gridReportConversions" height="100%" width="100%" dataProvider="{this.dp}" mouseEnabled="true" doubleClickEnabled="true" itemDoubleClick="refererRowDoubleClicked(event)"> <mx:columns> <mx:DataGridColumn width="75" dataField="qty" headerText="Qty" /> <mx:DataGridColumn dataField="referer" headerText="URL" /> </mx:columns> </mx:DataGrid> </mx:HBox>

  Read the article

• Fluent config not generating mapping files

  - by rboarman

  Hello, I am trying to get Fluent nHibernate to generate mappings so I can take a look at the files and the sql. My code is based on this post and on what I can glean from the documentation. http://stackoverflow.com/questions/1375146/fluent-mapping-entities-and-classmaps-in-different-assemblies I am using the latest code from git. Here’s my config code: Configuration cfg = new Configuration(); var ft = Fluently.Configure(cfg); //DbConnection by fluent ft.Database ( MsSqlConfiguration .MsSql2008 .ConnectionString("……") .ShowSql() .UseReflectionOptimizer() ); //get mapping files. ft.Mappings(m => { //set up the mapping locations m.FluentMappings.AddFromAssemblyOf<Entity>() .ExportTo(@"C:\temp"); m.Apply(cfg); }); I also tried: var sessionFactory = Fluently.Configure() .Database(MsSqlConfiguration .MsSql2008 .ShowSql() .ConnectionString(“……")) .Mappings(p => p.FluentMappings .AddFromAssemblyOf<Entity>() .ExportTo(@"c:\temp\")) .BuildSessionFactory(); I have verified that the connection string is correct. The issue is that no mapping files show up in the ExportTo folder and no sql code shows up in the output window or in the log file. No errors or exceptions are generated either. I have no idea where to go from here. Thank you in advance. Rick

  Read the article

• Detection of page refresh / F5 key in ASP.NET MVC 2

  - by Michael

  How would one go about detecting a page refresh / F5 key push on the controller handling the postback? I need to distinguish between the user pressing one of two buttons (e.g., Next, Previous) and when the F5 / page refresh occurs. My scenario is a single wizard page that has different content shown between each invocation of the user pressing the "Next" or "Previous" buttons. The error that I am running into is when the user refreshes the page / presses the F5 key, the browser re-sends the request back to the controller, which is handled as a post-back and the FormCollection type is used to look for the "submitButton" key and obtain its value (e.g., "Next," "Send"). This part was modeled after the post by Dylan Beattie at http://stackoverflow.com/questions/442704/how-do-you-handle-multiple-submit-buttons-in-asp-net-mvc-framework. Maybe I'm trying to bend MVC 2 to where it isn't meant to go but I'd like to stay with the current design in that the underlying database drives the content and order of what is shown. This allows us to add new content into the database without modifying the code the displays the content. Thanks, Michael

  Read the article

• Flex 4 vs JavaScript Options (Cappuccino, JQuery, etc.)

  - by user320681

  Rehashing an older post: http://stackoverflow.com/questions/1570070/jquery-vs-flex-choosing-a-platform-for-saas We are preparing to develop an application that is exceptionally dynamic and interactive. It's particularly heavy on the graphics side. We are 85% convinced that Adobe Flash built atop Flex is the right path to take, however Cappuccino is quite nice and seems as though it may be able to nearly fit the bill. The only pause we have right now is portability for the iPhone. With the lack of blessings from Apple we will most certainly have to create a 2nd interface for the iPhone for the site, however... Having two interfaces may not be bad as it will likely have to be custom anyway to take advantage of the differences that it affords. Any further thoughts or reevaluations of points enumerated in the noted article? Further, Flex 4 adds a lot of strength to the position mentioned previously regarding UI development. Fx4 is very nice vs Fx3 and shaves 90% from the development time when coupled with Flash Catalyst, which is not really always fully appropriate, but with some round trip tricks it seems as though it can cut through things rather well... Please do advise and many thanks.

  Read the article

• how to create wizard forms in ruby on rails

  - by Branden Silva

  I'm trying to understand the best options for pulling off a wizard form in ruby on rails. Ideally I'd like to have it so the application signup has a back and next button that allows the user to submit data in steps. So in step 1 they could fill out contact info. Once they are done they could click next and be on step 2 to fill out payment info, etc. If they make a mistake, they can click back and correct it. Some steps will be required, while others will not, but you do have to make it to the last step to submit the data to the database to sign up. They then need the ability to go back and fill out the past steps in the same fashion after completion. (example: perhaps if they clicked on a profile link they could recomplete the steps in the same fashion because they didn't want to complete all the steps right away. Maybe by being given a skip button before they completed the steps to sign up?). I also need validation to happen on what steps have been completed preventing them from moving onto the next step until corrected or completed. Option 1) I've noticed that ajax has been recommended as an option in other questions on stackoverflow. The only problem I have with it is that the user would not be able to sign up if javascript was disabled. Ideally I'd like to have it be native to ruby on rails but I'm willing to work with whatever is necessary to get it to work.

  Read the article

• Time to start returning IQueryable<T> instead of IList<T> to my Web UI / Web API Layer?

  - by JohnnyO

  I've got a multi-layer application that starts with the repository pattern for all data access and it returns IQueryable to the Services layer. The Services layer, which includes all of the business logic, returns IList to the Controllers (note: I'm using ASP.NET MVC for the UI layer). The benefit of returning IQueryable in the data access layer is that it allows my repositories to be extremely simple and the database queries to be deferred. However, I'm triggering the database queries in my services layer so that my unit tests is more reliable and I don't give flexibility to the Controllers to reshape my queries. However, I've recently encountered several situations where deferring the execution of queries down to the Controllers would have been significantly more performant because the Controllers had to do some projections on the data that was UI specific. Additionally, with the emergence of things like oData, I was starting to wonder if end points (e.g. web UI or web apis) should be working directly with IQueryable. What are your thoughts? Is it time to start returning IQueryable from the services layer to the UI layer? Or stick with IList? This thread here: http://stackoverflow.com/questions/718624/to-return-iqueryablet-or-not-return-iqueryablet seems to vouch for returning IList to the UI layers, but I was wondering if things are changing because of new emerging technologies and techniques.

  Read the article

• Create a SSL certificate on Windows

  - by Ben Fransen

  Hi all, Since I'm very new to SSL certificates, and the creation and usage of them I figured maybe StackOverflow members can help me out. I'm from Holland, the common way of online payments is by implementing iDEAL. An online payment protocol supported by the major banks. I have to implement a 'professional' version. This includes creating a RSA private key. Based on that key I have to create a certificate and upload it to the webserver. I'm on a Windows machine and completely confused what to do. I took a look at the OpenSSL website, because the manual forwarded me to that website to get a SSL Toolkit. The manual provides two commands which have to be executed in order to create a RSA key and a certificate. The commands are: openssl genrsa -des3 –out priv.pem -passout pass:myPassword 1024 and openssl req -x509 -new -key priv.pem -passin pass:myPassword -days 3650 -out cert.cer Is there a way I can do this by a utility on a windows machine? I've downloaded PuTTy KeyGenerator. But I'm not sure what to do, I've created a key (SSH-2 RSA, whatever that is..) but how do I create a certificate with that key? Any help is much appreciated! Ben

  Read the article

• ffmpeg(libavcodec). memory leaks in avcodec_encode_video

  - by gavlig

  I'm trying to transcode a video with help of libavcodec. On transcoding big video files(hour or more) i get huge memory leaks in avcodec_encode_video. I have tried to debug it, but with different video files different functions produce leaks, i have got a little bit confused about that :). [Here] (http://stackoverflow.com/questions/4201481/ffmpeg-with-qt-memory-leak) is the same issue that i have, but i have no idea how did that person solve it. QtFFmpegwrapper seems to do the same i do(or i missed something). my method is lower. I took care about aFrame and aPacket outside with av_free and av_free_packet. int Videocut::encode( AVStream *anOutputStream, AVFrame *aFrame, AVPacket *aPacket ) { AVCodecContext *outputCodec = anOutputStream->codec; if (!anOutputStream || !aFrame || !aPacket) { return 1; /* NOTREACHED */ } uint8_t * buffer = (uint8_t *)malloc( sizeof(uint8_t) * _DefaultEncodeBufferSize ); if (NULL == buffer) { return 2; /* NOTREACHED */ } int packetSize = avcodec_encode_video( outputCodec, buffer, _DefaultEncodeBufferSize, aFrame ); if (packetSize < 0) { free(buffer); return 1; /* NOTREACHED */ } aPacket->data = buffer; aPacket->size = packetSize; return 0; }

  Read the article

• Call long running operation in WSS feature OnActivated Event

  - by dirq

  More specifically - How do I reference SPContext in Web Service with [SoapDocumentMethod(OneWay=true)]? We are creating a feature that needs to run a job when a site is created. The job takes about 4 minutes to complete. So, we made a web service that we can call when the feature is activated. This works but we want it to run asynchronously now. We've found the SoapDocumentMethod's OneWay property and that would work awesomely but the SPContext is now NULL. We have our web services in the _vti_bin virtual directory so it's available in each Windows Sharepoint Services site. I was using the SPContext.Current.Web to get the site and perform the long running operation. I wanted to just fire and forget about it by returning a soap response right away and letting the process run. How can I get the current SPContext? I used to be able to do this in my web service: SPWeb mySite = SPContext.Current.Web; Can I get the same context when I have the [SoapDocumentMethod(OneWay=true)] attribute applied to my web service? Or must I recreate the SPWeb from the url? This is similar to this thread: http://stackoverflow.com/questions/340192/webservice-oneway-and-new-spsitemyurl Update: I've tried these two ways but they didn't work: SPWeb targetSite = SPControl.GetContextWeb(this.Context); SPWeb targetSite2 = SPContext.GetContext(this.Context).Web;

  Read the article

• javascript addEventListener onStateChange not working in IE

  - by user347456

  Hi, I have two colorbox popup boxes which show a youtube video in each. When they're finished playing, I'm trying to have them automatically close the colorbox window. This code below works perfect in firefox, but in IE I can't get addEventListener to work. I've tried attachEvent with no success. Can anybody offer any suggestions as to how to solve this? It seems simple but I'm exhausted trying to find a solution. By the way, this is my first time as stackoverflow and it's very impressive. var params = { allowScriptAccess: "always" }; var atts = { id: "ytplayer1" }; swfobject.embedSWF("http://www.youtube.com/v/VIDEO1&rel=0&hl=en_US&fs=0&autoplay=1&enablejsapi=1&playerapiid=ytvideo1", "popupVideoContainer1", "640", "385", "8", null, null, params, atts); var params2 = { allowScriptAccess: "always" }; var atts2 = { id: "ytplayer2" }; swfobject.embedSWF("http://www.youtube.com/v/VIDEO2&rel=0&hl=en_US&fs=0&autoplay=1&enablejsapi=1&playerapiid=ytvideo2", "popupVideoContainer2", "640", "385", "8", null, null, params2, atts2); function onYouTubePlayerReady(playerId) { if(playerId == 'ytvideo1'){ var ytplayer = document.getElementById('ytplayer1'); ytplayer.addEventListener("onStateChange", "onytplayerStateChange", false); } else if(playerId == 'ytvideo2'){ var ytplayer = document.getElementById("ytplayer2"); //ytplayer.addEventListener("onStateChange", "onytplayerStateChange", false); if (ytplayer.addEventListener) { ytplayer.addEventListener("onStateChange", "onytplayerStateChange", false); } else if (ytplayer.attachEvent) { ytplayer.attachEvent("onStateChange", onytplayerStateChange); } } } function onytplayerStateChange(newState) { if(newState == 0){ $.fn.colorbox.close(); } }

  Read the article

• WPF data validation is overriding theme on the interface

  - by black sensei

  Hello! Good People I built a WPF application and manage to get the validation working thanks to posts on stackoverflow.The only probblem i'm having is that it's overriding the theme i'm using. example the theme makes the textboxes look like a round rectangle but after setting the binding it look like the default textboxes. here is my code : <Button.Style> <Style TargetType="{x:Type Button}"> <Setter Property="IsEnabled" Value="false" /> <Style.Triggers> <!-- Require the controls to be valid in order to press OK --> <MultiDataTrigger> <MultiDataTrigger.Conditions> <Condition Binding="{Binding ElementName=txtEmail, Path=(Validation.HasError)}" Value="false" /> </MultiDataTrigger.Conditions> <Setter Property="IsEnabled" Value="true" /> </MultiDataTrigger> </Style.Triggers> </Style> </Button.Style> code behind is : //Form loaded event code txtEmail.GetBindingExpression(TextBox.TextProperty).UpdateSource(); I've tried to look into the theme file but i was quickly lost.i thought i could use that file like a web css file.Now i've disabled the data binding because of that.Is there any work around for this? thanks for reading this

  Read the article

• Alternative native api for Process.Start

  - by Akash Kava

  Ok this is not duplicate of "http://stackoverflow.com/questions/2065592/alternative-to-process-start" because my question is something different here. I need to run a process and wait till execution of process and get the output of console. There is way to set RedirectStandardOutput and RedirectStandardError to true, however this does not function well on some machines, (where .NET SDK is not installed), only .NET runtime is installed, now it works on some machines and doesnt work on some machines so we dont know where is the problem. I have following code, ProcessStartInfo info = new ProcessStartInfo("myapp.exe", cmd); info.CreateNoWindow = true; info.UseShellExecute = false; info.RedirectStandardError = true; info.RedirectStandardOutput = true; Process p = Process.Start(info); p.WaitForExit(); Trace.WriteLine(p.StandardOutput.ReadToEnd()); Trace.WriteLine(p.StandardError.ReadToEnd()); On some machines, this will hang forever on p.WaitForExit(), and one some machine it works correctly, the behaviour is so random and there is no clue. Now if I can get a real good workaround for this using pinvoke, I will be very happy.

  Read the article

• Query on simple C++ threadpool implementation

  - by ticketman

  Stackoverflow has been a tremendous help to me and I'd to give something back to the community. I have been implementing a simple threadpool using the tinythread C++ portable thread library, using what I have learnt from Stackoverflow. I am new to thread programming, so not that comfortable with mutexes, etc. I have a question best asked after presenting the code (which runs quite well under Linux): // ThreadPool.h class ThreadPool { public: ThreadPool(); ~ThreadPool(); // Creates a pool of threads and gets them ready to be used void CreateThreads(int numOfThreads); // Assigns a job to a thread in the pool, but doesn't start the job // Each SubmitJob call will use up one thread of the pool. // This operation can only be undone by calling StartJobs and // then waiting for the jobs to complete. On completion, // new jobs may be submitted. void SubmitJob( void (*workFunc)(void *), void *workData ); // Begins execution of all the jobs in the pool. void StartJobs(); // Waits until all jobs have completed. // The wait will block the caller. // On completion, new jobs may be submitted. void WaitForJobsToComplete(); private: enum typeOfWorkEnum { e_work, e_quit }; class ThreadData { public: bool ready; // thread has been created and is ready for work bool haveWorkToDo; typeOfWorkEnum typeOfWork; // Pointer to the work function each thread has to call. void (*workFunc)(void *); // Pointer to work data void *workData; ThreadData() : ready(false), haveWorkToDo(false) { }; }; struct ThreadArgStruct { ThreadPool *threadPoolInstance; int threadId; }; // Data for each thread ThreadData *m_ThreadData; ThreadPool(ThreadPool const&); // copy ctor hidden ThreadPool& operator=(ThreadPool const&); // assign op. hidden // Static function that provides the function pointer that a thread can call // By including the ThreadPool instance in the void * parameter, // we can use it to access other data and methods in the ThreadPool instance. static void ThreadFuncWrapper(void *arg) { ThreadArgStruct *threadArg = static_cast<ThreadArgStruct *>(arg); threadArg->threadPoolInstance->ThreadFunc(threadArg->threadId); } // The function each thread calls void ThreadFunc( int threadId ); // Called by the thread pool destructor void DestroyThreadPool(); // Total number of threads available // (fixed on creation of thread pool) int m_numOfThreads; int m_NumOfThreadsDoingWork; int m_NumOfThreadsGivenJobs; // List of threads std::vector<tthread::thread *> m_ThreadList; // Condition variable to signal each thread has been created and executing tthread::mutex m_ThreadReady_mutex; tthread::condition_variable m_ThreadReady_condvar; // Condition variable to signal each thread to start work tthread::mutex m_WorkToDo_mutex; tthread::condition_variable m_WorkToDo_condvar; // Condition variable to signal the main thread that // all threads in the pool have completed their work tthread::mutex m_WorkCompleted_mutex; tthread::condition_variable m_WorkCompleted_condvar; }; cpp file: // // ThreadPool.cpp // #include "ThreadPool.h" // This is the thread function for each thread. // All threads remain in this function until // they are asked to quit, which only happens // when terminating the thread pool. void ThreadPool::ThreadFunc( int threadId ) { ThreadData *myThreadData = &m_ThreadData[threadId]; std::cout << "Hello world: Thread " << threadId << std::endl; // Signal that this thread is ready m_ThreadReady_mutex.lock(); myThreadData->ready = true; m_ThreadReady_condvar.notify_one(); // notify the main thread m_ThreadReady_mutex.unlock(); while(true) { //tthread::lock_guard<tthread::mutex> guard(m); m_WorkToDo_mutex.lock(); while(!myThreadData->haveWorkToDo) // check for work to do m_WorkToDo_condvar.wait(m_WorkToDo_mutex); // if no work, wait here myThreadData->haveWorkToDo = false; // need to do this before unlocking the mutex m_WorkToDo_mutex.unlock(); // Do the work switch(myThreadData->typeOfWork) { case e_work: std::cout << "Thread " << threadId << ": Woken with work to do\n"; // Do work myThreadData->workFunc(myThreadData->workData); std::cout << "#Thread " << threadId << ": Work is completed\n"; break; case e_quit: std::cout << "Thread " << threadId << ": Asked to quit\n"; return; // ends the thread } // Now to signal the main thread that my work is completed m_WorkCompleted_mutex.lock(); m_NumOfThreadsDoingWork--; // Unsure if this 'if' would make the program more efficient // if(NumOfThreadsDoingWork == 0) m_WorkCompleted_condvar.notify_one(); // notify the main thread m_WorkCompleted_mutex.unlock(); } } ThreadPool::ThreadPool() { m_numOfThreads = 0; m_NumOfThreadsDoingWork = 0; m_NumOfThreadsGivenJobs = 0; } ThreadPool::~ThreadPool() { if(m_numOfThreads) { DestroyThreadPool(); delete [] m_ThreadData; } } void ThreadPool::CreateThreads(int numOfThreads) { // Check a thread pool has already been created if(m_numOfThreads > 0) return; m_NumOfThreadsGivenJobs = 0; m_NumOfThreadsDoingWork = 0; m_numOfThreads = numOfThreads; m_ThreadData = new ThreadData[m_numOfThreads]; ThreadArgStruct threadArg; for(int i=0; i<m_numOfThreads; ++i) { threadArg.threadId = i; threadArg.threadPoolInstance = this; // Creates the thread and save in a list so we can destroy it later m_ThreadList.push_back( new tthread::thread( ThreadFuncWrapper, (void *)&threadArg ) ); // It takes a little time for a thread to get established. // Best wait until it gets established before creating the next thread. m_ThreadReady_mutex.lock(); while(!m_ThreadData[i].ready) // Check if thread is ready m_ThreadReady_condvar.wait(m_ThreadReady_mutex); // If not, wait here m_ThreadReady_mutex.unlock(); } } // Adds a job to the batch, but doesn't start the job void ThreadPool::SubmitJob(void (*workFunc)(void *), void *workData) { // Check that the thread pool has been created if(!m_numOfThreads) return; if(m_NumOfThreadsGivenJobs >= m_numOfThreads) return; m_ThreadData[m_NumOfThreadsGivenJobs].workFunc = workFunc; m_ThreadData[m_NumOfThreadsGivenJobs].workData = workData; std::cout << "Submitted job " << m_NumOfThreadsGivenJobs << std::endl; m_NumOfThreadsGivenJobs++; } void ThreadPool::StartJobs() { // Check that the thread pool has been created // and some jobs have been assigned if(!m_numOfThreads || !m_NumOfThreadsGivenJobs) return; // Set 'haveworkToDo' flag for all threads m_WorkToDo_mutex.lock(); for(int i=0; i<m_NumOfThreadsGivenJobs; ++i) m_ThreadData[i].haveWorkToDo = true; m_NumOfThreadsDoingWork = m_NumOfThreadsGivenJobs; // Reset this counter so we can resubmit jobs later m_NumOfThreadsGivenJobs = 0; // Notify all threads they have work to do m_WorkToDo_condvar.notify_all(); m_WorkToDo_mutex.unlock(); } void ThreadPool::WaitForJobsToComplete() { // Check that a thread pool has been created if(!m_numOfThreads) return; m_WorkCompleted_mutex.lock(); while(m_NumOfThreadsDoingWork > 0) // Check if all threads have completed their work m_WorkCompleted_condvar.wait(m_WorkCompleted_mutex); // If not, wait here m_WorkCompleted_mutex.unlock(); } void ThreadPool::DestroyThreadPool() { std::cout << "Ask threads to quit\n"; m_WorkToDo_mutex.lock(); for(int i=0; i<m_numOfThreads; ++i) { m_ThreadData[i].haveWorkToDo = true; m_ThreadData[i].typeOfWork = e_quit; } m_WorkToDo_condvar.notify_all(); m_WorkToDo_mutex.unlock(); // As each thread terminates, catch them here for(int i=0; i<m_numOfThreads; ++i) { tthread::thread *t = m_ThreadList[i]; // Wait for thread to complete t->join(); } m_numOfThreads = 0; } Example of usage: (this calculates pi-squared/6) struct CalculationDataStruct { int inputVal; double outputVal; }; void LongCalculation( void *theSums ) { CalculationDataStruct *sums = (CalculationDataStruct *)theSums; int terms = sums->inputVal; double sum; for(int i=1; i<terms; i++) sum += 1.0/( double(i)*double(i) ); sums->outputVal = sum; } int main(int argc, char** argv) { int numThreads = 10; // Create pool ThreadPool threadPool; threadPool.CreateThreads(numThreads); // Create thread workspace CalculationDataStruct sums[numThreads]; // Set up jobs for(int i=0; i<numThreads; i++) { sums[i].inputVal = 3000*(i+1); threadPool.SubmitJob(LongCalculation, &sums[i]); } // Run the jobs threadPool.StartJobs(); threadPool.WaitForJobsToComplete(); // Print results for(int i=0; i<numThreads; i++) std::cout << "Sum of " << sums[i].inputVal << " terms is " << sums[i].outputVal << std::endl; return 0; } Question: In the ThreadPool::ThreadFunc method, would better performance be obtained if the following if statement if(NumOfThreadsDoingWork == 0) was included? Also, I'd be grateful of criticisms and ways to improve the code. At the same time, I hope the code is of use to others.

  Read the article

• Variant datatype library for C

  - by Joey Adams

  Is there a decent open-source C library for storing and manipulating dynamically-typed variables (a.k.a. variants)? I'm primarily interested in atomic values (int8, int16, int32, uint, strings, blobs, etc.), while JSON-style arrays and objects as well as custom objects would also be nice. A major case where such a library would be useful is in working with SQL databases. The most obvious feature of such a library would be a single type for all supported values, e.g.: struct Variant { enum Type type; union { int8_t int8_; int16_t int16_; // ... }; }; Other features might include converting Variant objects to/from C structures (using a binding table), converting values to/from strings, and integration with an existing database library such as SQLite. Note: I do not believe this is question is a duplicate of http://stackoverflow.com/questions/649649/any-library-for-generic-datatypes-in-c , which refers to "queues, trees, maps, lists". What I'm talking about focuses more on making working with SQL databases roughly as smooth as working with them in interpreted languages.

  Read the article

• Adding User License Agreement in Solaris package

  - by Adil

  I have asked similar question for Linux RPM (http://stackoverflow.com/questions/2132828/adding-license-agreement-in-rpm-package). Now i have same query for Solaris package. I could not get any helpful link / details if it is possible. But I have found a package which does exactly the same thing but how it has been implemented, its not mentioned. $pkgadd -d . SUNWsamfsr SUNWsamfsu Processing package instance from Sun SAM and Sun SAM-QFS software Solaris 10 (root)(i386) 4.6.5,REV=5.10.2007.03.12 Sun SAMFS - Storage & Archiving Management File System Copyright (c) 2007 Sun Microsystems, Inc. All Rights Reserved. ----------------------------------------------------- In order to install SUNWsamfsr, you must accept the terms of the Sun License Agreement. Enter "y" if you do, "n" if you don't, or "v" to view agreement. y -The administrator commands will be executable by root only (group bin). If this is the desired value, enter "y". If you want to change the specified value enter "c". y ... ... Any ideas how to implement such thing for Solaris package?

  Read the article

• Android ignores scrollbarsize

  - by Maragues

  Hi, I'm trying to modify a ListView scrollbar's width without success <ListView android:id="@+id/android:list" android:layout_width="fill_parent" android:layout_height="wrap_content" android:choiceMode="singleChoice" android:scrollbars="vertical" android:scrollbarTrackVertical="@drawable/scrollbar_vertical_track" android:scrollbarThumbVertical="@drawable/scrollbar_vertical_thumb" android:scrollbarSize="4px" android:clickable="true"/> First I tried using a drawable image 4px wide, but the .png was resized. Then I tried using a shape extracted from SamplesApi, without success. <shape xmlns:android="http://schemas.android.com/apk/res/android" android:width="40px"> <gradient android:startColor="#505050" android:endColor="#C0C0C0" android:angle="0"/> <corners android:radius="0dp" /> I've tried with and without the android:width attribute. There's a question on the same topic (http://stackoverflow.com/questions/2565083/width-of-a-scroll-bar-in-android), but it doesn't try anything different that what I'm already trying. As far as I know, creating my own theme shouldn't change the output. There's an example in SamplesApi (Views/ScrollBars). I tried modifying the scrollbarSize attribute without result. I know about ninepatch images, but there's an attribute which should do what I want. Any hint? Thanks in advance.

  Read the article

• How do I use a different image for each JQuery UI Slider handle

  - by Tom

  I'm using a JQuery UI slider which has two handles (a.k.a range slider). I know how to style the first handle: .ui-slider-horizontal .ui-slider-handle {background: white url(http://stackoverflow.com/content/img/so/vote-arrow-down.png) no-repeat scroll 50% 50%;} But how do I style the second handle differently? Using Firebug I can see Jquery does not uniquely identify each handle: <div id="hourlyRateSlider" class="ui-slider ui-slider-horizontal ui-widget ui-widget-content ui-corner-all"> <div class="ui-slider-range ui-widget-header" style="left: 26%; width: 46%;"/> <a class="ui-slider-handle ui-state-default ui-corner-all" href="#" style="left: 26%;"/> <a class="ui-slider-handle ui-state-default ui-corner-all" href="#" style="left: 72%;"/> </div> So I imagine I have to use either a CSS child selector which could be cross-browser problematic. Or I could use some JQuery trickery to add a CSS class to the second handle? Anyone done this in a neat way before?

  Read the article

• glitchy stuttery iphone game loop

  - by Adam

  This is a problem I've been trying to solve for a few days now, and I've looked at the various solutions on stackoverflow and nothing has really seemed to work for me. I'm making an iPhone game with OpenGLES graphics and accelerometer input, at this point it's very simple, but the rendering is already pretty bad... it stutters and seems to jump back or forward in time. It doesn't happen a lot, but it happens enough to be a problem. I mean, who wants to play a game where a bullet gets magically transported into the player, and then it's game over? No one. I've tried using NSTimer for the game loop, I've tried using a separate thread (with a frame rate and continuously) I've tried using different frame rates, from 30FPS to 60FPS (It seems to have a max frame rate around 45FPS, but no problems at 30FPS) I've tried using timeIntervalSince1970 and CFGetAbsoluteTime to measure loop time, with no noticeable diffence Anyone have any ideas on what is the best way to get this looking better? One of the posts I've read suggested running the simulation at a fixed frame rate and then just render as fast as possible, does that seem like a good idea?

  Read the article

< Previous Page | 158 159 160 161 162 163 164 165 166 167 168 169  | Next Page >