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• How to avoid loop limitation in a openvz container?

  - by mat.viguier

  On a openVZ containing Deb7 I need to lock the maximum size of a folder, which is used to upload on a php based web server. The directory is synced, so I have to lock the maxsize. MAXSIZE should be upgradable by adding some physical disk later ... I want to use a file as a block device for a file system. So I have done : dd if=/dev/zero of=/disk2/filesystem.dat bs=1M count=100 Then, I made the filesystem on it mkfs.ext4 filesystem.dat Then I tried to mount it : mkdir /opt/filesystem ; mount /disk2/filesystem.dat /opt/filesystem My OpenVZ (it is on a VPS) has no loop module in the kernerl. So I got Could not find any loop device as usual under OpenVz So i think I have to use FUSE, but I really do not know HOW .... Any idea on locking the size of directory under OpenVZ ?

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• How can I avoid Firefox's "you have chosen to open" dialog when I try to download a file?

  - by mjtsai

  I just want it to save the file to disk, not bring up a dialog and make me click "Save File" each time. The file types that I'm downloading are not listed in Firefox's Applications preferences, and I see no way to add them. I'm using Firefox 3.6.2.

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• Can i change the subnet on the vpn side of a server without having to change its whole lan (to avoid collission)

  - by Gusty

  Ohai, ive got a xp server with a client connecting via VPN. Problem (as we all know) is that sometimes the subnets clash. Instead of changing the whole server network every time this happens, cant i just have the server appear to have a different subnet to vpn clients? I have no interest in accessing other computers than the server on its LAN. I tried just turning off automatic dhcp in the servers vpn settings and changed it to 172.31.255.x. The client gets the address assigned alright and it can ping 172.31.255.1 but i cannot ping the server name (because the dns on the clients vpn connection points at 192.168.0.1?) wisdom? PS everything worked until the client hit a network with the same subnet as the server lan. thanks

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• Tuning Nvidia driver in Nvidia X Server Settings in Ubuntu to avoid tearing?

  - by c00kiemonster

  I'm running Ubuntu 10.10 on an Asus at3ion motherboard. I have installed the proprietary nvidia drivers and everything is working fine, but it's a but ragged when I move windows etc. I think the issue is called tearing. There is flickering and the window isn't refreshed smoothly. The ion acceleration works fine (I am running xbmc at 1080p completely without any issues). Please note I am not interested in any fancy effects etc, I just want the graphics to be smooth and nice. How can I tune the nvidia driver for this, i.e., what do I need to change in the Nvidia X Server Settings?

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• How can I avoid Excel reformatting the scientific notation numbers I enter?

  - by Diomidis Spinellis

  When I enter a number like 8230e12 into a Microsoft Excel 2000 cell, Excel changes the number I entered into 8230000000000000. (This is what I get when I press F2 to edit the cell's contents, not what Excel displays in the cell). How can I force Excel to keep the data in the format I typed it and still be able to format it and use it as a number? Displaying the cell in scientific notation is not enough, because the exponent is not the same one as the one I typed.

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• How to avoid specifying full path in sudoers file?

  - by s g

  I am trying to add a NOPASSWD entry for sudotest.sh (or any script/binary that requires sudo) in my /etc/sudoers file (on Ubuntu 12.04 LTS server), but in order to make it work, I must specify the full path. The following entry works just fine: %jenkins ALL=(ALL)NOPASSWD:/home/vts_share/test/sudotest.sh The problem is that the script might move to a different directory. This seems like a great chance to use the * wildcard in the path (i.e. /*/sudotest.sh) so that my script could be in any directory but the manual states that wildcards will not match the / character when used in a path. I've confirmed that it doesn't work. I know that I can use the word ALL in place of my script, but this means there is no password prompt for any commands which seems unsafe. How do I solve this?

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• how to change user interface language in firefox to avoid so-called localization?

  - by hugh featherstone

  since yesterday my firefox thinks that everyone in belgium speaks flemish. this is a typically american problem: americans NEVER seem to know where languages are spoken (i think they just guess) but for some reason believe that language localization software is cool. it is NOT, it is a curse. so suddenly i no longer have my user interface in english (which was fine) but now in flemish, which looks and reads like a tongue disease and is not even the second language of the area i live in (first language here is german, second is french). how can i change back to english?

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• How to avoid loading a LINQ to SQL object twice when editting it on a website.

  - by emzero

  Hi guys I know you are all tired of this Linq-to-Sql questions, but I'm barely starting to use it (never used an ORM before) and I've already find some "ugly" things. I'm pretty used to ASP.NET Webforms old school developing, but I want to leave that behind and learn the new stuff (I've just started to read a ASP.NET MVC book and a .NET 3.5/4.0 one). So here's is one thing I didn't like and I couldn't find a good alternative to it. In most examples of editing a LINQ object I've seen the object is loaded (hitting the db) at first to fill the current values on the form page. Then, the user modify some fields and when the "Save" button is clicked, the object is loaded for second time and then updated. Here's a simplified example of ScottGu NerdDinner site. // // GET: /Dinners/Edit/5 [Authorize] public ActionResult Edit(int id) { Dinner dinner = dinnerRepository.GetDinner(id); return View(new DinnerFormViewModel(dinner)); } // // POST: /Dinners/Edit/5 [AcceptVerbs(HttpVerbs.Post), Authorize] public ActionResult Edit(int id, FormCollection collection) { Dinner dinner = dinnerRepository.GetDinner(id); UpdateModel(dinner); dinnerRepository.Save(); return RedirectToAction("Details", new { id=dinner.DinnerID }); } As you can see the dinner object is loaded two times for every modification. Unless I'm missing something about LINQ to SQL caching the last queried objects or something like that I don't like getting it twice when it should be retrieved only one time, modified and then comitted back to the database. So again, am I really missing something? Or is it really hitting the database twice (in the example above it won't harm, but there could be cases that getting an object or set of objects could be heavy stuff). If so, what alternative do you think is the best to avoid double-loading the object? Thank you so much, Greetings!

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• Is there a way to avoid spaghetti code over the years?

  - by Yoni Roit

  I've had several programming jobs. Each one with 20-50 developers, project going on for 3-5 years. Every time it's the same. Some programmers are bright, some are average. Everyone has their CS degree, everyone read design patterns. Intentions are good, people are trying hard to write good code but still after a couple of years the code turns into spaghetti. Changes in module A suddenly break module B. There are always these parts of code that no one can understand except for the person who wrote it. Changing infrastructure is impossible and backwards compatibility issues prevent good features to get in. Half of the time you just want to rewrite everything from scratch. And people more experienced than me treat this as normal. Is it? Does it have to be? What can I do to avoid this or should I accept it as a fact of life? Edit: Guys, I am impressed with the amount and quality of responses here. This site and its community rock!

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• Servlet Mapping Help - Possible to Avoid Referencing Context Name?

  - by AJ

  Hi all, I am working on a Spring application and trying to get my URL mapping correct. What I would like to have work is the following: http://localhost:8080/idptest -> doesn't work But instead, I have to reference the context name in my URL in order to resolve the mapping: http://localhost:8080/<context_name>/idptest -> works How can I avoid the requirement of referencing the context name in my URL without using a rewrite/proxy engine e.g. Apache? Here is the servlet definition and mapping from my web.xml: <servlet> <servlet-name>idptest</servlet-name> <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class> <init-param> <param-name>contextConfigLocation</param-name> <param-value>/WEB-INF/conf/idptest.xml</param-value> </init-param> <load-on-startup>1</load-on-startup> </servlet> <servlet-mapping> <servlet-name>idptest</servlet-name> <url-pattern>/</url-pattern> </servlet-mapping> Here's the outline of my controller (showing annotations for request mappings): @Controller @RequestMapping("/idptest") public class MyController { @RequestMapping(method=RequestMethod.GET) public String setupForm(Model model){ MyObject someObject = new MyObject(); model.addAttribute("someObject", someObject); return "myform"; } @RequestMapping(method = RequestMethod.POST) public String processSubmit(@ModelAttribute("someObject") MyObject someObject) throws Exception { // POST logic... } } Thanks!

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• iPhone: Leak with UIWebView loading Office documents. Any ideas how to avoid it?

  - by Thomas Tempelmann

  While there are already quite a few posts about leaks around UIWebView, mine is a bit more special, I believe, and thus deserves its own post here. I see a reproducible large leak every time I load a Office document such as a Word or Excel file. For instance, every time I display a 180KB .doc file, I get a 100KB leak. And that happens with both the simulator and an actual device, running OS 3.1.3. The leak is not visible with the Leaks instrument but only by looking at the malloc instances via the ObjectAlloc instrument. Here's a picture from the instruments trace: I've also made a demo project, UIWebView-Leak.zip, so you can verify this yourself. To see the leak, use the ObjectAlloc instrument, switch to the view where you see individual allocation objects, and sort by size so that you see the large ones in a group, just like in my picture above. Then view a Office document a few times and find the Malloc objects that keep staying "Live" even after the actual UIWebView has been freed. Is this a known bug? Or is there any way I can avoid these leaks? I.e, have you successfully shown Office documents on an iPhone withing getting such leaks? Note: I've reported this as a bug to Apple now, too (ID 7950594) I am still waiting for someone (including Apple) to confirm this as a true leak or show why it isn't (i.e. that I do something wrong or make wrong assumptions)

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• Avoid existing files being overwritten when newer version is installed.

  - by constant learner

  Hello I have a VS2008 windows application project (WinProject) which is deployed by the installation project (InstallationProject) which inturn has the property RemovePreviousVersions set to True. In my app for each configuration made by an user, the winapp writes the configurations into an xml file (stored in C:\Application Name\Files\ folder) which also includes the path where the config was saved. Now when I build new versions of the installer,This folder and the files are overwritten since i the flag AlwaysCreate is set to True. My question is how can i avoid these older files from being overwritten and at the same time shall get the updated file from the installer. Ex: Contents of the file <PriceFiles> <Name>arr</Name> <Path>C:\NewTool\arr.xml</Path> <UserDefined>true</UserDefined> </PriceFiles> <ReferenceProjects> <Name>studio</Name> <Path>C:\NewTool\ReferenceProjects\6cd3a9e9-ad65-475e-953b-128915a496cd.xml</Path> <UserDefined>true</UserDefined> <CreatedBy>Admin</CreatedBy> </ReferenceProjects> Thanks in advance

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• Can a WebServiceHost be changed to avoid the use of HttpListener?

  - by sbyse

  I am looking for a way to use a WCF WebServiceHost without having to rely on the HttpListener class and it's associated permission problems (see this question for details). I'm working on a application which communicates locally with another (third-party) application via their REST API. At the moment we are using WCF as an embedded HTTP server. We create a WebServiceHost as follows: String hostPath = "http://localhost:" + portNo; WebServiceHost host = new WebServiceHost(typeof(IntegrationService), new Uri(hostPath)); // create a webhttpbinding for rest/pox and enable cookie support for session management WebHttpBinding webHttpBinding = new WebHttpBinding(); webHttpBinding.AllowCookies = true; ServiceEndpoint ep = host.AddServiceEndpoint(typeof(IIntegrationService), webHttpBinding, ""); host.Open() ChannelFactory<IIntegrationService> cf = new ChannelFactory<IIntegrationService>(webHttpBinding, hostPath); IIntegrationService channel = cf.CreateChannel(); Everything works nicely as long as our application is run as administrator. If we run our application on a machine without administrative privileges the host.Open() will throw an HttpListenerException with ErrorCode == 5 (ERROR_ACCESS_DENIED). We can get around the problem by running httpcfg.exe from the command line but this is a one-click desktop application and that's not really as long term solution for us. We could ditch WCF and write our own HTTP server but I'd like to avoid that if possible. What's the easiest way to replace HttpListener with a standard TCP socket while still using all of the remaining HTTP scaffolding that WCF provides?

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• How to avoid the following purify detected memory leak in C++?

  - by Abhijeet

  Hi, I am getting the following memory leak.Its being probably caused by std::string. how can i avoid it? PLK: 23 bytes potentially leaked at 0xeb68278 * Suppressed in /vobs/ubtssw_brrm/test/testcases/.purify [line 3] * This memory was allocated from: malloc [/vobs/ubtssw_brrm/test/test_build/linux-x86/rtlib.o] operator new(unsigned) [/vobs/MontaVista/Linux/montavista/pro/devkit/x86/586/target/usr/lib/libstdc++.so.6] operator new(unsigned) [/vobs/ubtssw_brrm/test/test_build/linux-x86/rtlib.o] std::string<char, std::char_traits<char>, std::allocator<char>>::_Rep::_S_create(unsigned, unsigned, std::allocator<char> const&) [/vobs/MontaVista/Linux/montavista/pro/devkit/ x86/586/target/usr/lib/libstdc++.so.6] std::string<char, std::char_traits<char>, std::allocator<char>>::_Rep::_M_clone(std::allocator<char> const&, unsigned) [/vobs/MontaVista/Linux/montavista/pro/devkit/x86/586/tar get/usr/lib/libstdc++.so.6] std::string<char, std::char_traits<char>, std::allocator<char>>::string<char, std::char_traits<char>, std::allocator<char>>(std::string<char, std::char_traits<char>, std::alloc ator<char>> const&) [/vobs/MontaVista/Linux/montavista/pro/devkit/x86/586/target/usr/lib/libstdc++.so.6] uec_UEDir::getEntryToUpdateAfterInsertion(rcapi_ImsiGsmMap const&, rcapi_ImsiGsmMap&, std::_Rb_tree_iterator<std::pair<std::string<char, std::char_traits<char>, std::allocator< char>> const, UEDirData >>&) [/vobs/ubtssw_brrm/uectrl/linux-x86/../src/uec_UEDir.cc:2278] uec_UEDir::addUpdate(rcapi_ImsiGsmMap const&, LocalUEDirInfo&, rcapi_ImsiGsmMap&, int, unsigned char) [/vobs/ubtssw_brrm/uectrl/linux-x86/../src/uec_UEDir.cc:282] ucx_UEDirHandler::addUpdateUEDir(rcapi_ImsiGsmMap, UEDirUpdateType, acap_PresenceEvent) [/vobs/ubtssw_brrm/ucx/linux-x86/../src/ucx_UEDirHandler.cc:374]

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• Is this the intention behavior in JComboBox? How I can avoid this behavior?

  - by Yan Cheng CHEOK

  I realize that if you are having a same selection in JComboBox, using up/down arrow key, will not help you to navigate the selection around. How I can avoid this behavior? See the below screen shoot /* * To change this template, choose Tools | Templates * and open the template in the editor. */ /* * NewJFrame.java * * Created on May 8, 2010, 7:46:28 PM */ package javaapplication26; /** * * @author yccheok */ public class NewJFrame extends javax.swing.JFrame { /** Creates new form NewJFrame */ public NewJFrame() { initComponents(); /* If you are having 3 same strings here. Using, up/down arrow key, * will not move the selection around. */ this.jComboBox1.addItem("Intel"); this.jComboBox1.addItem("Intel"); this.jComboBox1.addItem("Intel"); } /** This method is called from within the constructor to * initialize the form. * WARNING: Do NOT modify this code. The content of this method is * always regenerated by the Form Editor. */ @SuppressWarnings("unchecked") // <editor-fold defaultstate="collapsed" desc="Generated Code"> private void initComponents() { jComboBox1 = new javax.swing.JComboBox(); setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE); jComboBox1.setEditable(true); javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane()); getContentPane().setLayout(layout); layout.setHorizontalGroup( layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) .addGroup(layout.createSequentialGroup() .addGap(105, 105, 105) .addComponent(jComboBox1, javax.swing.GroupLayout.PREFERRED_SIZE, 158, javax.swing.GroupLayout.PREFERRED_SIZE) .addContainerGap(137, Short.MAX_VALUE)) ); layout.setVerticalGroup( layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) .addGroup(layout.createSequentialGroup() .addGap(63, 63, 63) .addComponent(jComboBox1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE) .addContainerGap(217, Short.MAX_VALUE)) ); pack(); }// </editor-fold> /** * @param args the command line arguments */ public static void main(String args[]) { java.awt.EventQueue.invokeLater(new Runnable() { public void run() { new NewJFrame().setVisible(true); } }); } // Variables declaration - do not modify private javax.swing.JComboBox jComboBox1; // End of variables declaration }

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• JSF myfaces dataTable , how to avoid NBSP; tags in the TDs

  - by Peter

  Hi, I have style applied to the TD elements of the dataTable of my myfaces application. td.financialReportTd { font-family: Arial; font-size: 12px; line-height: 12px; color:black; background-color: white; padding-right: 5px; text-align: right; border:0px black solid; height: 30px; padding-top:4px; padding-left:4px; vertical-align: top; direction: rtl; } Output: <td class="financialReportTd"> &nbsp;&nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;MY TEXT </td> No matter what I try, those NBSP tags fill up the TD and position of the text changes to the worse. I tried style text-align:right; (I need RTL text), I tried direction: rtl; Nothing helps. How can I align my text to the very right of the TD and avoid those space tags?

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• Progressive enhancement of anchor tags to avoid onclick="return false;"

  - by Chris Beck

  Unobtrusive JS suggests that we don't have any onclick attributes in our HTML templates. <a href="/controller/foo/1">View Foo 1</a> A most basic progressive enhancement is to convert an that anchor tag to use XHR to retrieve a DOM fragment. So, I write JS to add an event listener for a."click" then make an XHR to a.href. Alas, the browser still wants to navigate to "/controller/foo". So, I write JS to dynamically inject a.onclick = "return false;". Still unobtrusive (I guess), but now I'm paying the the cost of an extra event handler. To avoid the cost of 2 event listeners, I could shove my function call into the onclick attribute <a href="/controller/foo/1" onclick="myXHRFcn(); return false;"> But that's grodo for all sorts of reasons. To make it more interesting, I might have 100 anchor tags that I want to enhance. A better pattern is a single listener on a parent node that relies on event bubbling. That's cool, but how do I short circuit the browser from navigating to the URL without this on every anchor node? onclick="return false;" Manipulating the href is not an option. It must stay intact so the context menu options to copy or open in new page work as expected.

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• How can I avoid encoding mixups of strings in a C/C++ API?

  - by Frerich Raabe

  I'm working on implementing different APIs in C and C++ and wondered what techniques are available for avoiding that clients get the encoding wrong when receiving strings from the framework or passing them back. For instance, imagine a simple plugin API in C++ which customers can implement to influence translations. It might feature a function like this: const char *getTranslatedWord( const char *englishWord ); Now, let's say that I'd like to enforce that all strings are passed as UTF-8. Of course I'd document this requirement, but I'd like the compiler to enforce the right encoding, maybe by using dedicated types. For instance, something like this: class Word { public: static Word fromUtf8( const char *data ) { return Word( data ); } const char *toUtf8() { return m_data; } private: Word( const char *data ) : m_data( data ) { } const char *m_data; }; I could now use this specialized type in the API: Word getTranslatedWord( const Word &englishWord ); Unfortunately, it's easy to make this very inefficient. The Word class lacks proper copy constructors, assignment operators etc.. and I'd like to avoid unnecessary copying of data as much as possible. Also, I see the danger that Word gets extended with more and more utility functions (like length or fromLatin1 or substr etc.) and I'd rather not write Yet Another String Class. I just want a little container which avoids accidental encoding mixups. I wonder whether anybody else has some experience with this and can share some useful techniques. EDIT: In my particular case, the API is used on Windows and Linux using MSVC 6 - MSVC 10 on Windows and gcc 3 & 4 on Linux.

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• R optimization: How can I avoid a for loop in this situation?

  - by chrisamiller

  I'm trying to do a simple genomic track intersection in R, and running into major performance problems, probably related to my use of for loops. In this situation, I have pre-defined windows at intervals of 100bp and I'm trying to calculate how much of each window is covered by the annotations in mylist. Graphically, it looks something like this: 0 100 200 300 400 500 600 windows: |-----|-----|-----|-----|-----|-----| mylist: |-| |-----------| So I wrote some code to do just that, but it's fairly slow and has become a bottleneck in my code: ##window for each 100-bp segment windows <- numeric(6) ##second track mylist = vector("list") mylist[[1]] = c(1,20) mylist[[2]] = c(120,320) ##do the intersection for(i in 1:length(mylist)){ st <- floor(mylist[[i]][1]/100)+1 sp <- floor(mylist[[i]][2]/100)+1 for(j in st:sp){ b <- max((j-1)*100, mylist[[i]][1]) e <- min(j*100, mylist[[i]][2]) windows[j] <- windows[j] + e - b + 1 } } print(windows) [1] 20 81 101 21 0 0 Naturally, this is being used on data sets that are much larger than the example I provide here. Through some profiling, I can see that the bottleneck is in the for loops, but my clumsy attempt to vectorize it using *apply functions resulted in code that runs an order of magnitude more slowly. I suppose I could write something in C, but I'd like to avoid that if possible. Can anyone suggest another approach that will speed this calculation up?

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• How to avoid raising an event to a closed form?

  - by Steve Dignan

  I'm having trouble handling the scenario whereby an event is being raised to a closed form and was hoping to get some help. Scenario (see below code for reference): Form1 opens Form2 Form1 subscribes to an event on Form2 (let's call the event FormAction) Form1 is closed and Form2 remains open Form2 raises the FormAction event In Form1.form2_FormAction, why does this return a reference to Form1 but button1.Parent returns null? Shouldn't they both return the same reference? If we were to omit step 3, both this and button1.Parent return the same reference. Here's the code I'm using... Form1: public partial class Form1 : Form { public Form1 () { InitializeComponent(); } private void button1_Click ( object sender , EventArgs e ) { // Create instance of Form2 and subscribe to the FormAction event var form2 = new Form2(); form2.FormAction += form2_FormAction; form2.Show(); } private void form2_FormAction ( object o ) { // Always returns reference to Form1 var form = this; // If Form1 is open, button1.Parent is equal to form/this // If Form1 is closed, button1.Parent is null var parent = button1.Parent; } } Form2: public partial class Form2 : Form { public Form2 () { InitializeComponent(); } public delegate void FormActionHandler ( object o ); public event FormActionHandler FormAction = delegate { }; private void button1_Click ( object sender , EventArgs e ) { FormAction( "Button clicked." ); } } Ideally, I would like to avoid raising events to closed/disposed forms (which I'm not sure is possible) or find a clean way of handling this in the caller (in this case, Form1). Any help is appreciated.

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• How to avoid concurrent execution of a time-consuming task without blocking?

  - by Diego V

  I want to efficiently avoid concurrent execution of a time-consuming task in a heavily multi-threaded environment without making threads wait for a lock when another thread is already running the task. Instead, in that scenario, I want them to gracefully fail (i.e. skip its attempt to execute the task) as fast as possible. To illustrate the idea considerer this unsafe (has race condition!) code: private static boolean running = false; public void launchExpensiveTask() { if (running) return; // Do nothing running = true; try { runExpensiveTask(); } finally { running = false; } } I though about using a variation of Double-Checked Locking (consider that running is a primitive 32-bit field, hence atomic, it could work fine even for Java below 5 without the need of volatile). It could look like this: private static boolean running = false; public void launchExpensiveTask() { if (running) return; // Do nothing synchronized (ThisClass.class) { if (running) return; running = true; try { runExpensiveTask(); } finally { running = false; } } } Maybe I should also use a local copy of the field as well (not sure now, please tell me). But then I realized that anyway I will end with an inner synchronization block, that still could hold a thread with the right timing at monitor entrance until the original executor leaves the critical section (I know the odds usually are minimal but in this case we are thinking in several threads competing for this long-running resource). So, could you think in a better approach?

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• Could this C cast to avoid a signed/unsigned comparison make any sense?

  - by sharptooth

  I'm reviewing a C++ project and see effectively the following: std::vector<SomeType> objects; //then later int size = (int)objects.size(); for( int i = 0; i < size; ++i ) { process( objects[i] ); } Here's what I see. std::vector::size() returns size_t that can be of some size not related to the size of int. Even if sizeof(int) == sizeof(size_t) int is signed and can't hold all possible values of size_t. So the code above could only process the lower part of a very long vector and contains a bug. That said I'm curious of why the author might have written this? My only guess is that first he omitted the (int) cast and the compiler emitted something like Visual C++ C4018 warning: warning C4018: '<' : signed/unsigned mismatch so the author though that the best way to avoid the compiler warning would be to simply cast the size_t to int thus making the compiler shut up. Is there any other possible sane reason for that C cast?

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• jQuery.getJSON: how to avoid requesting the json-file on every refresh? (caching)

  - by Mr. Bombastic

  in this example you can see a generated HTML-list. On every refresh the script requests the data-file (ajax/test.json) and builds the list again. The generated file "ajax/test.json" is cached statically. But how can I avoid requesting this file on every refresh? // source: jquery.com $.getJSON('ajax/test.json', function(data) { var items = []; $.each(data, function(key, val) { items.push('<li id="' + key + '">' + val + '</li>'); }); $('<ul/>', { 'class': 'my-new-list', html: items. }).appendTo('body'); }); This doesn't work: list_data = $.cookie("list_data"); if (list_data == undefined || list_data == "") { $.getJSON('ajax/test.json', function(data) { list_data = data; }); } var items = []; $.each(data, function(key, val) { items.push('<li id="' + key + '">' + val + '</li>'); }); $('<ul/>', { 'class': 'my-new-list', html: items. }).appendTo('body'); Thanks in advance!

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• What should I do or don't do to avoid Delphi "push dword" bug.

  - by Maksee

  I found that Delphi 5 generates invalid assembly code in specific cases. I can't understand in what cases in general. The example below produces access violation since a very strange optimization occurs. For a byte in a record or array Delphi generates push dword [...], pop ebx, mov .., bl that works correctly if there are data after this byte (we need at least three to push dword correctly), but fails if the data is inaccessible. I emulated the strict boundaries here with win32 Virtual* functions Specifically the error occurs when the last byte from the block accessed inside FeedBytesToClass procedure. And if I try to change something like using data array instead of object property of remove actionFlag variable, Delphi generates correct assembly instructions. const BlockSize = 4096; type TSomeClass = class private fBytes: PByteArray; public property Bytes: PByteArray read fBytes; constructor Create; destructor Destroy;override; end; constructor TSomeClass.Create; begin inherited Create; GetMem(fBytes, BlockSize); end; destructor TSomeClass.Destroy; begin FreeMem(fBytes); inherited; end; procedure FeedBytesToClass(SrcDataBytes: PByteArray; Count: integer); var j: integer; Ofs: integer; actionFlag: boolean; AClass: TSomeClass; begin AClass:=TSomeClass.Create; try actionFlag:=true; for j:=0 to Count-1 do begin Ofs:=j; if actionFlag then begin AClass.Bytes[Ofs]:=SrcDataBytes[j]; end; end; finally AClass.Free; end; end; procedure TForm31.Button1Click(Sender: TObject); var SrcDataBytes: PByteArray; begin SrcDataBytes:=VirtualAlloc(Nil, BlockSize, MEM_COMMIT, PAGE_READWRITE); try if VirtualLock(SrcDataBytes, BlockSize) then try FeedBytesToClass(SrcDataBytes, BlockSize); finally VirtualUnLock(SrcDataBytes, BlockSize); end; finally VirtualFree(SrcDataBytes, MEM_DECOMMIT, BlockSize); end; end; Initially the error occured when I used access to RGB data of bitmap bits, but the code there is too complex so I narrowed it to this fragment. So the question is what is here so specific that makes Delphi produce push,pop,mov optimization. I need to know this in order to avoid such side effects in general.

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• Call HttpWebRequest in another thread as UI with Task class - avoid to dispose object created in Task scope

  - by John

  I would like call HttpWebRequest on another thread as UI, because I must make 200 request or server and downloaded image. My scenation is that I make a request on server, create image and return image. This I make in another thread. I use Task class, but it call automaticaly Dispose method on all object created in task scope. So I return null object from this method. public BitmapImage CreateAvatar(Uri imageUri, int sex) { if (imageUri == null) return CreateDefaultAvatar(sex); BitmapImage image = null; new Task(() => { var request = WebRequest.Create(imageUri); var response = request.GetResponse(); using (var stream = response.GetResponseStream()) { Byte[] buffer = new Byte[response.ContentLength]; int offset = 0, actuallyRead = 0; do { actuallyRead = stream.Read(buffer, offset, buffer.Length - offset); offset += actuallyRead; } while (actuallyRead > 0); image = new BitmapImage { CreateOptions = BitmapCreateOptions.None, CacheOption = BitmapCacheOption.OnLoad }; image.BeginInit(); image.StreamSource = new MemoryStream(buffer); image.EndInit(); image.Freeze(); } }).Start(); return image; } How avoid it? Thank Mr. Jon Skeet try this: private Stream GetImageStream(Uri imageUri) { Byte[] buffer = null; //new Task(() => //{ var request = WebRequest.Create(imageUri); var response = request.GetResponse(); using (var stream = response.GetResponseStream()) { buffer= new Byte[response.ContentLength]; int offset = 0, actuallyRead = 0; do { actuallyRead = stream.Read(buffer, offset, buffer.Length - offset); offset += actuallyRead; } while (actuallyRead > 0); } //}).Start(); return new MemoryStream(buffer); } It return object which is null a than try this: private Stream GetImageStream(Uri imageUri) { Byte[] buffer = null; new Task(() => { var request = WebRequest.Create(imageUri); var response = request.GetResponse(); using (var stream = response.GetResponseStream()) { buffer= new Byte[response.ContentLength]; int offset = 0, actuallyRead = 0; do { actuallyRead = stream.Read(buffer, offset, buffer.Length - offset); offset += actuallyRead; } while (actuallyRead > 0); } }).Start(); return new MemoryStream(buffer); } Method above return null

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