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• How do I debug a difficult-to-reproduce crash with no useful call stack?

  - by David M

  I am encountering an odd crash in our software and I'm having a lot of trouble debugging it, and so I am seeking SO's advice on how to tackle it. The crash is an access violation reading a NULL pointer: First chance exception at $00CF0041. Exception class $C0000005 with message 'access violation at 0x00cf0041: read of address 0x00000000'. It only happens 'sometimes' - I haven't managed to figure out any rhyme or reason, yet, for when - and only in the main thread. When it occurs, the call stack contains one incorrect entry: For the main thread, which this is, it should show a large stack full of other items. At this point, all other threads are inactive (mostly sitting in WaitForSingleObject or a similar function.) I have only seen this crash occur in the main thread. It always has the same call stack of one entry, in the same method at the same address. This method may or may not be related - we do use the VCL in our application. My bet, though, is that something (possibly quite a while ago) is corrupting the stack, and the address where it's crashing is effectively random. Note it has been the same address across several builds, though - it's probably not truly random. Here is what I've tried: Trying to reproduce it reliably at a certain point. I have found nothing that reproduces it every time, and a couple of things that occasionally do, or do not, for no apparent reason. These are not 'narrow' enough actions to narrow it down to a particular section of code. It may be timing related, but at the point the IDE breaks in, other threads are usually doing nothing. I can't rule out a threading problem, but think it's unlikely. Building with extra debugging statements (extra debug info, extra asserts, etc.) After doing so, the crash never occurs. Building with Codeguard enabled. After doing so, the crash never occurs and Codeguard shows no errors. My questions: 1. How do I find what code caused the crash? How do I do the equivalent of walking back up the stack? 2. What general advice do you have for how to trace the cause of this crash? I am using Embarcadero RAD Studio 2010 (the project mostly contains C++ Builder code and small amounts of Delphi.)

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• Gradual memory leak in loop over contents of QTMovie

  - by Benji XVI

  I have a simple foundation tool that exports every frame of a movie as a .tiff file. Here is the relevant code: NSString* movieLoc = [NSString stringWithCString:argv[1]]; QTMovie *sourceMovie = [QTMovie movieWithFile:movieLoc error:nil]; int i=0; while (QTTimeCompare([sourceMovie currentTime], [sourceMovie duration]) != NSOrderedSame) { // save image of movie to disk NSAutoreleasePool *arp = [[NSAutoreleasePool alloc] init]; NSString *filePath = [NSString stringWithFormat:@"/somelocation_%d.tiff", i++]; NSData *currentImageData = [[sourceMovie currentFrameImage] TIFFRepresentation]; [currentImageData writeToFile:filePath atomically:NO]; NSLog(@"%@", filePath); [sourceMovie stepForward]; [arp release]; } [pool drain]; return 0; As you can see, in order to prevent very large memory buildups with the various transparently-autoreleased variables in the loop, we create, and flush, an autoreleasepool with every run through the loop. However, over the course of stepping through a movie, the amount of memory used by the program still gradually increases. Instruments is not detecting any memory leaks per se, but the object trace shows certain General Data blocks to be increasing in size. [Edited out reference to slowdown as it doesn't seem to be as much of a problem as I thought.] Edit: let's knock out some parts of the code inside the loop & see what we find out... Test 1 while (banana) { NSAutoreleasePool *arp = [[NSAutoreleasePool alloc] init]; NSString *filePath = [NSString stringWithFormat:@"/somelocation_%d.tiff", i++]; NSLog(@"%@", filePath); [sourceMovie stepForward]; [arp release]; } Here we simply loop over the whole movie, creating the filename and logging it. Memory characteristics: remains at 15MB usage for the duration. Test 2 while (banana) { NSAutoreleasePool *arp = [[NSAutoreleasePool alloc] init]; NSImage *image = [sourceMovie currentFrameImage]; [sourceMovie stepForward]; [arp release]; } Here we add back in the creation of the NSImage from the current frame. Memory characteristics: gradually increasing memory usage. RSIZE is at 60MB by frame 200; 75MB by f300. Test 3 while (banana) { NSAutoreleasePool *arp = [[NSAutoreleasePool alloc] init]; NSImage *image = [sourceMovie currentFrameImage]; NSData *imageData = [image TIFFRepresentation]; [sourceMovie stepForward]; [arp release]; } We've added back in the creation of an NSData object from the NSImage. Memory characteristics: Memory usage is again increasing: 62MB at f200; 75MB at f300. In other words, largely identical. It looks like a memory leak in the underlying system QTMovie uses to do currentFrameImage, to me.

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• DCVS + hosting for a startup commercial multiplatform phone app

  - by AG

  I'm in lean startup mode, working on a simple phone app that will be published initially as a iThingy app and an Android app with, possibly, Blackberry and Symbian versions to follow. I'm about to go from no repository to needing a central repository that up to 4 very part-time resources will be sharing. Two of us have no version control background, one has used Subversion, and I've used most of the major centralized VCS systems. I'm not going to be pushing the technical limitations of any VCS for a long time; I'm sure that any of the major systems would work fine. And the hosting accounts I've looked at seem reasonable. So I'm really focussed on minimizing the downside risks. That is, I'd like to find a stable setup that is easy to learn in general, easy to use from Windows/Eclipse, and won't paint me into any obvious corners for the next 12 months or so. A quick search of the web had led me to consider the following pairs of DVCS and hosting service, with what I think I'm hearing as their strengths and weaknesses (for my purposes): Bazaar/Launchpad -- My initial choice since I need to get more familiar with this pair for the Google Summer of Code mentoring I'm doing. But, whatever the technical merits, a non-starter for me because they are purely open source, no private repositories plans to purchase that I can see. Git/GitHub -- Git: Fast, light, ultimately flexible, but relatively less Windows friendly, Eclipse plugin (eGit) available but relatively young, GitHub: widely used, pricing is fine Mercurial/BitBucket -- Mercurial: a little less flexible, a little more Windows friendly, Eclipse plugin seems a bit more mature, BitBucket: widely used, pricing is fine, includes a wiki and an issue tracker that we might be able to use instead of something like BaseCamp, at least for a while. Mercurial/BitBucket seem like the winning pair so far for my particular situation; at least two of us are definitely going to be working mostly from Eclipse on Windows and reducing my own learning curve is a priority. ;-) But I have two specific questions: 1) Am I wrong about Bazaar/Launchpad and is there a viable, secure way to use them for proprietary code? 2) Any reason to think that the Mecurial/Bitbucket pair will end up being a headache for my Mac developer, soon, or for Blackberry or Symbian developers a little later? ag

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• Copy all childNodes to an other element. In javascript native way.

  - by kroko

  Hello I have to change "unknown" contents of XML. The structure and content itself is valid. Original <blabla foo="bar"> <aa>asas</aa> <ff> <cc> <dd /> </cc> </ff> <gg attr2="2"> </gg> ... ... </blabla> becomes <blabla foo="bar"> <magic> <aa>asas</aa> <ff> <cc> <dd /> </cc> </ff> <gg attr2="2"> </gg> ... ... </magic> </blabla> thus, adding a child straight under document root node (document.documentElement) and "pushing" the "original" children under that. Here it has to be done in plain javascript (ecmascript). The idea now is to // Get the root node RootNode = mymagicdoc.documentElement; // Create new magic element (that will contain contents of original root node) var magicContainer = mymagicdoc.createElement("magic"); // Copy all root node children (and their sub tree - deep copy) to magic node /* ????? here RootNodeClone = RootNode.cloneNode(true); RootNodeClone.childNodes...... */ // Remove all children from root node while(RootNode.hasChildNodes()) RootNode.removeChild(RootNode.firstChild); // Now when root node is empty add the magicContainer // node in it that contains all the children of original root node RootNode.appendChild(magicContainer); How to do that /* */ step? Or maybe someone has a much better solution in general for achieving the desirable result? Thank you in advance!

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• Android USB Host Communication

  - by Kip Russell

  I'm working on a project that utilizes the USB Host capabilities in Android 3.2. I'm suffering from a deplorable lack of knowledge and talent regarding USB/Serial communication in general. I'm also unable to find any good example code for what I need to do. I need to read from a USB Communication Device. Ex: When I connect via Putty (on my PC) I enter: >GO And the device starts spewing out data for me. Pitch/Roll/Temp/Checksum. Ex: $R1.217P-0.986T26.3*60 $R1.217P-0.986T26.3*60 $R1.217P-0.987T26.3*61 $R1.217P-0.986T26.3*60 $R1.217P-0.985T26.3*63 I can send the initial 'GO' command from the Android device at which time I receive an echo of 'GO'. Then nothing else on any subsequent reads. How can I: 1) Send the 'go' command. 2) Read in the stream of data that results. The USB device I'm working with has the following interfaces (endpoints). Device Class: Communication Device (0x2) Interfaces: Interface #0 Class: Communication Device (0x2) Endpoint #0 Direction: Inbound (0x80) Type: Intrrupt (0x3) Poll Interval: 255 Max Packet Size: 32 Attributes: 000000011 Interface #1 Class: Communication Device Class (CDC) (0xa) Endpoint #0 Address: 129 Number: 1 Direction: Inbound (0x80) Type: Bulk (0x2) Poll Interval (0) Max Packet Size: 32 Attributes: 000000010 Endpoint #1 Address: 2 Number: 2 Direction: Outbound (0x0) Type: Bulk (0x2) Poll Interval (0) Max Packet Size: 32 Attributes: 000000010 I'm able to deal with permission, connect to the device, find the correct interface and assign the endpoints. I'm just having trouble figuring out which technique to use to send the initial command read the ensuing data. I'm tried different combinations of bulkTransfer and controlTransfer with no luck. Thanks. I'm using interface#1 as seen below: public AcmDevice(UsbDeviceConnection usbDeviceConnection, UsbInterface usbInterface) { Preconditions.checkState(usbDeviceConnection.claimInterface(usbInterface, true)); this.usbDeviceConnection = usbDeviceConnection; UsbEndpoint epOut = null; UsbEndpoint epIn = null; // look for our bulk endpoints for (int i = 0; i < usbInterface.getEndpointCount(); i++) { UsbEndpoint ep = usbInterface.getEndpoint(i); Log.d(TAG, "EP " + i + ": " + ep.getType()); if (ep.getType() == UsbConstants.USB_ENDPOINT_XFER_BULK) { if (ep.getDirection() == UsbConstants.USB_DIR_OUT) { epOut = ep; } else if (ep.getDirection() == UsbConstants.USB_DIR_IN) { epIn = ep; } } } if (epOut == null || epIn == null) { throw new IllegalArgumentException("Not all endpoints found."); } AcmReader acmReader = new AcmReader(usbDeviceConnection, epIn); AcmWriter acmWriter = new AcmWriter(usbDeviceConnection, epOut); reader = new BufferedReader(acmReader); writer = new BufferedWriter(acmWriter); }

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• JSON or YAML encoding in GWT/Java on both client and server

  - by KennethJ

  I'm looking for a super simple JSON or YAML library (not particularly bothered which one) written in Java, and can be used in both GWT on the client, and in its original Java form on the server. What I'm trying to do is this: I have my models, which are shared between the client and the server, and these are the primary source of data interchange. I want to design the web service in between to be as simple as possible, and decided to take the RESTful approach. My problem is that I know our application will grow substantially in the future, and writing all the getters, setters, serialization, factories, etc. by hand fills me with absolute dread. So in order to avoid it, I decided to implement annotations to keep track of attributes on the models. The reason I can't just serialize everything directly, using GWT's own one, or one which works through reflection, is because we need a certain amount of logic going on in the serialization process. I.e. whether references to other models get serialized during the serialization of the original model, or whether an ID is just passed, and general simple things like that. I've then written an annotation processor to preprocess my shared models and generate an implementing class with all the getters, setters, serialization, lazy-loading, etc. To make a long story short, I need some type of simple YAML or JSON library, which allows me to encode and decode manually, so I can generate this code through my annotation processor. I have had a look around the interwebs, but every single one I ran into supported some reflection which, while all fine and dandy, make it pretty much useless for GWT. And in the case of GWT's own JSON library, it uses JSNI for speed purposes, making it useless server side. One solution I did think about involved writing writing two sets of serialization methods on the models, one for the client and one for the server, but I'd rather not do that. Also, I'm pretty new to GWT, and even though I have done a lot of Java, it was back in the 1.2 days, so it's a bit rusty. So if you think I'm going about this problem completely the wrong way, I'm open to suggestions.

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• Overwhelmed by design patterns... where to begin?

  - by Pete

  I am writing a simple prototype code to demonstrate & profile I/O schemes (HDF4, HDF5, HDF5 using parallel IO, NetCDF, etc.) for a physics code. Since focus is on IO, the rest of the program is very simple: class Grid { public: floatArray x,y,z; }; class MyModel { public: MyModel(const int &nip1, const int &njp1, const int &nkp1, const int &numProcs); Grid grid; map<string, floatArray> plasmaVariables; }; Where floatArray is a simple class that lets me define arbitrary dimensioned arrays and do mathematical operations on them (i.e. x+y is point-wise addition). Of course, I could use better encapsulation (write accessors/setters, etc.), but that's not the concept I'm struggling with. For the I/O routines, I am envisioning applying simple inheritance: Abstract I/O class defines read & write functions to fill in the "myModel" object HDF4 derived class HDF5 HDF5 using parallel IO NetCDF etc... The code should read data in any of these formats, then write out to any of these formats. In the past, I would add an AbstractIO member to myModel and create/destroy this object depending on which I/O scheme I want. In this way, I could do something like: myModelObj.ioObj->read('input.hdf') myModelObj.ioObj->write('output.hdf') I have a bit of OOP experience but very little on the Design Patterns front, so I recently acquired the Gang of Four book "Design Patterns: Elements of Reusable Object-Oriented Software". OOP designers: Which pattern(s) would you recommend I use to integrate I/O with the myModel object? I am interested in answering this for two reasons: To learn more about design patterns in general Apply what I learn to help refactor an large old crufty/legacy physics code to be more human-readable & extensible. I am leaning towards applying the Decerator pattern to myModel, so I can attach the I/O responsibilities dynamically to myModel (i.e. whether to use HDF4, HDF5, etc.). However, I don't feel very confident that this is the best pattern to apply. Reading the Gang of Four book cover-to-cover before I start coding feels like a good way to develop an unhealthy caffeine addiction. What patterns do you recommend?

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• Coroutines in Java

  - by JUST MY correct OPINION

  I would like to do some stuff in Java that would be clearer if written using concurrent routines, but for which full-on threads are serious overkill. The answer, of course, is the use of coroutines, but there doesn't appear to be any coroutine support in the standard Java libraries and a quick Google on it brings up tantalising hints here or there, but nothing substantial. Here's what I've found so far: JSIM has a coroutine class, but it looks pretty heavyweight and conflates, seemingly, with threads at points. The point of this is to reduce the complexity of full-on threading, not to add to it. Further I'm not sure that the class can be extracted from the library and used independently. Xalan has a coroutine set class that does coroutine-like stuff, but again it's dubious if this can be meaningfully extracted from the overall library. It also looks like it's implemented as a tightly-controlled form of thread pool, not as actual coroutines. There's a Google Code project which looks like what I'm after, but if anything it looks more heavyweight than using threads would be. I'm basically nervous of something that requires software to dynamically change the JVM bytecode at runtime to do its work. This looks like overkill and like something that will cause more problems than coroutines would solve. Further it looks like it doesn't implement the whole coroutine concept. By my glance-over it gives a yield feature that just returns to the invoker. Proper coroutines allow yields to transfer control to any known coroutine directly. Basically this library, heavyweight and scary as it is, only gives you support for iterators, not fully-general coroutines. The promisingly-named Coroutine for Java fails because it's a platform-specific (obviously using JNI) solution. And that's about all I've found. I know about the native JVM support for coroutines in the Da Vinci Machine and I also know about the JNI continuations trick for doing this. These are not really good solutions for me, however, as I would not necessarily have control over which VM or platform my code would run on. (Indeed any bytecode manipulation system would suffer similar problems -- it would be best were this pure Java if possible. Runtime bytecode manipulation would restrict me from using this on Android, for example.) So does anybody have any pointers? Is this even possible? If not, will it be possible in Java 7?

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• Looking for an Open Source Project in need of help

  - by hvidgaard

  Hi StackOverflow! I'm a CS student on well on my way to graduate. I have had a difficult time of finding relevant student jobs (they seems to be taken merely hours after the notice gets on the board) , so instead I'm looking for an open source project in need of help. I'm aware that I should choose one that I use, but I'm not aware of any OS-project that I use that needs help. That's why I'm asking you. I don't have any deep experience, but I here are some of my biggest projects so far: BitTorrent-ish client in Python (a subset of BitTorrent) HTTP 1.1 webserver in Java Compiler from a subset of Java to run on JRE Flash-framework project to model an iPad look and feel (not to run actual iPad programs) complete with an API for programs. Complete MySQL database for a booking system, with departure and arrival times, so you could only book valid tickets (with a Java frontend). I know, Java and languages like AS3 and C# feels natural per se, Python, and have done a fair bit of hacking around in C, but I don't feel very comfortable with it. Mostly I'm afraid to make a fuckup because I have such a high degree of control. I would like to think I'm well aware of good software design practices, but in reality what I do is ask myself "would I like to use/maintain this?", and I love to refactor my code because I see optimizations. I love algorithms and to make them run in the best possible time. I don't have any preferred domain to work in, but I wouldn't mind it to be graphics or math heavy. Ideally I'm looking for a project in C++ to learn the in's and out's of it, but I'm well aware that I don't know that language very well. I would like to have a mentor-like figure until I'm confident enough to stand on my own, not one to review all my code (I'm sure someone will to start with anyway), but to ask questions about the project and language in question. I do have a wife and two children, so don't expect me to put in 10+ hours every week. In return I can work on my own, I strive to program modular and maintainable code. Know how to read an API, use Google, StackOverflow and online resources in general. If you have any questions, shoot. I'm looking forward to your suggestions.

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• Symfony2 Entity to array

  - by Adriano Pedro

  I'm trying to migrate my flat php project to Symfony2, but its coming to be very hard. For instance, I have a table of Products specification that have several specifications and are distinguishables by its "cat" attribute in that Extraspecs DB table. Therefore I've created a Entity for that table and want to make an array of just the specifications with "cat" = 0... I supose the code is this one.. right? $typeavailable = $this->getDoctrine() ->getRepository('LabsCatalogBundle:ProductExtraspecsSpecs') ->findBy(array('cat' => '0')); Now how can i put this in an array to work with a form like this?: form = $this ->createFormBuilder($product) ->add('specs', 'choice', array('choices' => $typeavailableArray), 'multiple' => true) Thank you in advance :) # Thank you all.. But now I've came across with another problem.. In fact i'm building a form from an existing object: $form = $this ->createFormBuilder($product) ->add('name', 'text') ->add('genspec', 'choice', array('choices' => array('0' => 'None', '1' => 'General', '2' => 'Specific'))) ->add('isReg', 'choice', array('choices' => array('0' => 'Material', '1' => 'Reagent', '2' => 'Antibody', '3' => 'Growth Factors', '4' => 'Rodents', '5' => 'Lagomorphs'))) So.. in that case my current value is named "extraspecs", so i've added this like: ->add('extraspecs', 'entity', array( 'label' => 'desc', 'empty_value' => ' --- ', 'class' => 'LabsCatalogBundle:ProductExtraspecsSpecs', 'property' => 'specsid', 'query_builder' => function(EntityRepository $er) { return $er ->createQueryBuilder('e'); But "extraspecs" come from a relationship of oneToMany where every product has several extraspecs... Here is the ORM: Labs\CatalogBundle\Entity\Product: type: entity table: orders__regmat id: id: type: integer generator: { strategy: AUTO } fields: name: type: string length: 100 catnumber: type: string scale: 100 brand: type: integer scale: 10 company: type: integer scale: 10 size: type: decimal scale: 10 units: type: integer scale: 10 price: type: decimal scale: 10 reqcert: type: integer scale: 1 isReg: type: integer scale: 1 genspec: type: integer scale: 1 oneToMany: extraspecs: targetEntity: ProductExtraspecs mappedBy: product Labs\CatalogBundle\Entity\ProductExtraspecs: type: entity table: orders__regmat__extraspecs fields: extraspecid: id: true type: integer unsigned: false nullable: false generator: strategy: IDENTITY regmatid: type: integer scale: 11 spec: type: integer scale: 11 attrib: type: string length: 20 value: type: string length: 200 lifecycleCallbacks: { } manyToOne: product: targetEntity: Product inversedBy: extraspecs joinColumn: name: regmatid referencedColumnName: id HOw should I do this? Thank you!!!

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• Separate specific #ifdef branches

  - by detly

  In short: I want to generate two different source trees from the current one, based only on one preprocessor macro being defined and another being undefined, with no other changes to the source. If you are interested, here is my story... In the beginning, my code was clean. Then we made a new product, and yea, it was better. But the code saw only the same peripheral devices, so we could keep the same code. Well, almost. There was one little condition that needed to be changed, so I added: #if defined(PRODUCT_A) condition = checkCat(); #elif defined(PRODUCT_B) condition = checkCat() && checkHat(); #endif ...to one and only one source file. In the general all-source-files-include-this header file, I had: #if !(defined(PRODUCT_A)||defined(PRODUCT_B)) #error "Don't make me replace you with a small shell script. RTFM." #endif ...so that people couldn't compile it unless they explicitly defined a product type. All was well. Oh... except that modifications were made, components changed, and since the new hardware worked better we could significantly re-write the control systems. Now when I look upon the face of the code, there are more than 60 separate areas delineated by either: #ifdef PRODUCT_A ... #else ... #endif ...or the same, but for PRODUCT_B. Or even: #if defined(PRODUCT_A) ... #elif defined(PRODUCT_B) ... #endif And of course, sometimes sanity took a longer holiday and: #ifdef PRODUCT_A ... #endif #ifdef PRODUCT_B ... #endif These conditions wrap anywhere from one to two hundred lines (you'd think that the last one could be done by switching header files, but the function names need to be the same). This is insane. I would be better off maintaining two separate product-based branches in the source repo and porting any common changes. I realise this now. Is there something that can generate the two different source trees I need, based only on PRODUCT_A being defined and PRODUCT_B being undefined (and vice-versa), without touching anything else (ie. no header inclusion, no macro expansion, etc)?

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• Facebook Like not Pulling Title

  - by matthewb

  I am having some issues with the new facebook like button. It shows up fine, however for some reason it's not pulling the title of the page. I have the and I am using og:title, all are filled in, when I view the source of the iframe created on the load of he button, the in there is blank. I am also trying to put the tweetmeme and that's seeing that title and not the meta, or the normal page title. What am I doing wrong? <html xmlns="http://www.w3.org/1999/xhtml" xmlns:og="http://opengraphprotocol.org/schema/" xmlns:fb="http://developers.facebook.com/schema/"> <fb:like href="<?=$url?>" layout="button_count" show_faces="false" width="100" font="arial"></fb:like> UPDATE: Complete Head <head> <title>Ladder 15 Gets A New Menu!</title> <meta content="Growing up can be hard to do, especially in the Mad River family. But Ladder 15 has come into its own over the winter.&nbsp; With some new cocktails, wine selection, a hefty new beer list and veteran Chef David Ansill in the kitchen, you can check your fist pump at" name="Description"> <meta content="" name="Keywords"> <meta content="cities2night inc." name="author"> <meta content="Cities2Night 2010" name="copyright"> <meta content="en-us" name="language"> <meta content="General" name="rating"> <meta content="index,follow" name="robots"> <meta content="text/html; charset=UTF-8" http-equiv="Content-Type"> <meta content="Ladder 15 gets a new menu!" name="tweetmeme-title"> <meta content="Ladder 15 gets a new menu!" property="og:title"> <meta content="article" property="og:type"> <meta content="http://philly.cities2night.com/articles/show/listing/11/ladder-15-gets-a-new-menu" property="og:url"> <meta content="http://philly.cities2night.com/public/article_images/11.jpg" property="og:image"> <meta content="c0176da0ec38aaf107c0ef6c8cdeee38" property="fb:app_id"> <meta content="Philly2night.com" property="og:site_name"> <meta content="Growing up can be hard to do, especially in the Mad River family. But Ladder" property="og:description"></head>

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• how to create a system-wide independent universal counter object primarily for Database keys?

  - by andora

  I would like to create/use a system-wide independent universal 'counter object' that can be called via COM in a thread-safe manner. The counter object will be passed an ID to identify which counter to return, handle the counting, 'persist' the count (occasionally), have reasonable performance (as fast as possible) perhaps capable of 1000 counts per second or better (1mS) and be accessible cross-process/out-of-process. The current count status must be persisted between object restarts/shutdowns. The counter object is liklely to be a 'singleton' type object implemented in some form of free-threaded dictionary, containing maybe 10 counters (perhaps 50 max). The count needs to be monotonic and consistent, (ie: guaranteed unique sequential values). Each counter should have a few methods, like reset, inc, dec, set, clear, remove. As a luxury, I would like to have a variable-increment (ie: 'step by' value). To support thread-safefty, perhaps some sorm of critical-section or mutex call. It just needs to return a long/4byte signed integer. I really want something that can be called from anywhere, including VBScript, so I figure COM is my preferred solution. The primary use of this is for database keys. I am unable to use autoinc or guid type keys and have ruled out database-generated counting systems at this point. I've spent days researching this and I have really struggled to find a solution. The best I can find is a free-threaded dictionary object that can be instantiated using COM+ from Motobit - it seems to offer all the 'basics' and I guess I could create some form of wrapper for this. So, here are my questions: Does such a 'general purpose counter-object already exist? Can you direct me to it? (MS did do an IIS/ASP object called 'MSWC.Counter' but this isn't 'cross-process'/ out-of-process component and isn't thread-safe. (but if it was, it would do!) What is the best way of creating such a Component? (I'd prefer VB6 right-now, [don't ask!] but can do in VB.NET2005 if I had to). I don't have the skills/knowledge/tools to use anything else. I am desparate for a workable solution. I need specific guidance! If anybody can code something up for me I am prepared to pay for it.

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• iPhone Debugger Message -- Weird

  - by Bill Shiff

  Hello, I have an iPhone app that I've been working on and have recently upgraded my version of XCode. Since the upgrade, I can build and debug in the iPhone Simulator just fine, but when I try to debug on an attached device I get the following messages: From Xcode4: GNU gdb 6.3.50-20050815 (Apple version gdb-1510) (Fri Oct 22 04:12:10 UTC 2010) Copyright 2004 Free Software Foundation, Inc. GDB is free software, covered by the GNU General Public License, and you are welcome to change it and/or distribute copies of it under certain conditions. Type "show copying" to see the conditions. There is absolutely no warranty for GDB. Type "show warranty" for details. This GDB was configured as "--host=i386-apple-darwin --target=arm-apple-darwin".tty /dev/ttys001 sharedlibrary apply-load-rules all warning: Unable to read symbols from "dyld" (prefix __dyld_) (not yet mapped into memory). warning: Unable to read symbols for (null)/Library/Frameworks/MessageUI.framework/MessageUI (file not found). warning: Unable to read symbols from "MessageUI" (not yet mapped into memory). warning: Unable to read symbols for (null)/Library/Frameworks/MapKit.framework/MapKit (file not found). warning: Unable to read symbols from "MapKit" (not yet mapped into memory). warning: Unable to read symbols from "Foundation" (not yet mapped into memory). warning: Unable to read symbols for (null)/Library/Frameworks/UIKit.framework/UIKit (file not found). warning: Unable to read symbols from "UIKit" (not yet mapped into memory). warning: Unable to read symbols for (null)/Library/Frameworks/CoreGraphics.framework/CoreGraphics (file not found). warning: Unable to read symbols from "CoreGraphics" (not yet mapped into memory). warning: Unable to read symbols from "CoreData" (not yet mapped into memory). warning: Unable to read symbols from "QuartzCore" (not yet mapped into memory). warning: Unable to read symbols from "libgcc_s.1.dylib" (not yet mapped into memory). warning: Unable to read symbols from "libSystem.B.dylib" (not yet mapped into memory). warning: Unable to read symbols from "libobjc.A.dylib" (not yet mapped into memory). warning: Unable to read symbols from "CoreFoundation" (not yet mapped into memory). target remote-mobile /tmp/.XcodeGDBRemote-3836-28 Switching to remote-macosx protocol mem 0x1000 0x3fffffff cache mem 0x40000000 0xffffffff none mem 0x00000000 0x0fff none [Switching to thread 11523] [Switching to thread 11523] gdb stack crawl at point of internal error: 0 gdb-arm-apple-darwin 0x0013216e internal_vproblem + 316

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• approximating log10[x^k0 + k1]

  - by Yale Zhang

  Greetings. I'm trying to approximate the function Log10[x^k0 + k1], where .21 < k0 < 21, 0 < k1 < ~2000, and x is integer < 2^14. k0 & k1 are constant. For practical purposes, you can assume k0 = 2.12, k1 = 2660. The desired accuracy is 5*10^-4 relative error. This function is virtually identical to Log[x], except near 0, where it differs a lot. I already have came up with a SIMD implementation that is ~1.15x faster than a simple lookup table, but would like to improve it if possible, which I think is very hard due to lack of efficient instructions. My SIMD implementation uses 16bit fixed point arithmetic to evaluate a 3rd degree polynomial (I use least squares fit). The polynomial uses different coefficients for different input ranges. There are 8 ranges, and range i spans (64)2^i to (64)2^(i + 1). The rational behind this is the derivatives of Log[x] drop rapidly with x, meaning a polynomial will fit it more accurately since polynomials are an exact fit for functions that have a derivative of 0 beyond a certain order. SIMD table lookups are done very efficiently with a single _mm_shuffle_epi8(). I use SSE's float to int conversion to get the exponent and significand used for the fixed point approximation. I also software pipelined the loop to get ~1.25x speedup, so further code optimizations are probably unlikely. What I'm asking is if there's a more efficient approximation at a higher level? For example: Can this function be decomposed into functions with a limited domain like log2((2^x) * significand) = x + log2(significand) hence eliminating the need to deal with different ranges (table lookups). The main problem I think is adding the k1 term kills all those nice log properties that we know and love, making it not possible. Or is it? Iterative method? don't think so because the Newton method for log[x] is already a complicated expression Exploiting locality of neighboring pixels? - if the range of the 8 inputs fall in the same approximation range, then I can look up a single coefficient, instead of looking up separate coefficients for each element. Thus, I can use this as a fast common case, and use a slower, general code path when it isn't. But for my data, the range needs to be ~2000 before this property hold 70% of the time, which doesn't seem to make this method competitive. Please, give me some opinion, especially if you're an applied mathematician, even if you say it can't be done. Thanks.

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• Calculating rotation and translation matrices between two odometry positions for monocular linear triangulation

  - by user1298891

  Recently I've been trying to implement a system to identify and triangulate the 3D position of an object in a robotic system. The general outline of the process goes as follows: Identify the object using SURF matching, from a set of "training" images to the actual live feed from the camera Move/rotate the robot a certain amount Identify the object using SURF again in this new view Now I have: a set of corresponding 2D points (same object from the two different views), two odometry locations (position + orientation), and camera intrinsics (focal length, principal point, etc.) since it's been calibrated beforehand, so I should be able to create the 2 projection matrices and triangulate using a basic linear triangulation method as in Hartley & Zissermann's book Multiple View Geometry, pg. 312. Solve the AX = 0 equation for each of the corresponding 2D points, then take the average In practice, the triangulation only works when there's almost no change in rotation; if the robot even rotates a slight bit while moving (due to e.g. wheel slippage) then the estimate is way off. This also applies for simulation. Since I can only post two hyperlinks, here's a link to a page with images from the simulation (on the map, the red square is simulated robot position and orientation, and the yellow square is estimated position of the object using linear triangulation.) So you can see that the estimate is thrown way off even by a little rotation, as in Position 2 on that page (that was 15 degrees; if I rotate it any more then the estimate is completely off the map), even in a simulated environment where a perfect calibration matrix is known. In a real environment when I actually move around with the robot, it's worse. There aren't any problems with obtaining point correspondences, nor with actually solving the AX = 0 equation once I compute the A matrix, so I figure it probably has to do with how I'm setting up the two camera projection matrices, specifically how I'm calculating the translation and rotation matrices from the position/orientation info I have relative to the world frame. How I'm doing that right now is: Rotation matrix is composed by creating a 1x3 matrix [0, (change in orientation angle), 0] and then converting that to a 3x3 one using OpenCV's Rodrigues function Translation matrix is composed by rotating the two points (start angle) degrees and then subtracting the final position from the initial position, in order to get the robot's straight and lateral movement relative to its starting orientation Which results in the first projection matrix being K [I | 0] and the second being K [R | T], with R and T calculated as described above. Is there anything I'm doing really wrong here? Or could it possibly be some other problem? Any help would be greatly appreciated.

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• A NSMutableArray is destroying my life!

  - by camilo

  EDITED to show the relevant part of the code Hi. There's a strange problem with an NSMutableArray which I'm just not understanding... Explaining: I have a NSMutableArray, defined as a property (nonatomic, retain), synthesized, and initialized with 29 elements. realSectionNames = [[NSMutableArray alloc] initWithCapacity:29]; After the initialization, I can insert elements as I wish and everything seems to be working fine. While I'm running the application, however, if I insert a new element in the array, I can print the array in the function where I inserted the element, and everything seems ok. However, when I select a row in the table, and I need to read that array, my application crashes. In fact, it cannot even print the array anymore. Is there any "magical and logical trick" everybody should know when using a NSMutableArray that a beginner like myself can be missing? Thanks a lot. I declare my array as realSectionNames = [[NSMutableArray alloc] initWithCapacity:29]; I insert objects in my array with [realSectionNames addObject:[category categoryFirstLetter]]; although I know i can also insert it with [realSectionNames insertObject:[category categoryFirstLetter] atIndex:i]; where the "i" is the first non-occupied position. After the insertion, I reload the data of my tableView. Printing the array before or after reloading the data shows it has the desired information. After that, selecting a row at the table makes the application crash. This realSectionNames is used in several UITableViewDelegate functions, but for the case it doesn't matter. What truly matters is that printing the array in the beginning of the didSelectRowAtIndexPath function crashes everything (and of course, doesn't print anything). I'm pretty sure it's in that line, for printing anything he line before works (example): NSLog(@"Anything"); NSLog(@"%@", realSectionNames); gives the output: 2010-03-24 15:16:04.146 myApplicationExperience[3527:207] Anything [Session started at 2010-03-24 15:16:04 +0000.] GNU gdb 6.3.50-20050815 (Apple version gdb-967) (Tue Jul 14 02:11:58 UTC 2009) Copyright 2004 Free Software Foundation, Inc. GDB is free software, covered by the GNU General Public License, and you are welcome to change it and/or distribute copies of it under certain conditions. Type "show copying" to see the conditions. There is absolutely no warranty for GDB. Type "show warranty" for details. This GDB was configured as "i386-apple-darwin".sharedlibrary apply-load-rules all Attaching to process 3527. Still not understanding what kind of stupidity I've done this time... maybe it's not too late to follow the career of brain surgeon?

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• Multi-threaded Pooled Allocators

  - by Darren Engwirda

  I'm having some issues using pooled memory allocators for std::list objects in a multi-threaded application. The part of the code I'm concerned with runs each thread function in isolation (i.e. there is no communication or synchronization between threads) and therefore I'd like to setup separate memory pools for each thread, where each pool is not thread-safe (and hence fast). I've tried using a shared thread-safe singleton memory pool and found the performance to be poor, as expected. This is a heavily simplified version of the type of thing I'm trying to do. A lot has been included in a pseudo-code kind of way, sorry if it's confusing. /* The thread functor - one instance of MAKE_QUADTREE created for each thread */ class make_quadtree { private: /* A non-thread-safe memory pool for int linked list items, let's say that it's * something along the lines of BOOST::OBJECT_POOL */ pooled_allocator<int> item_pool; /* The problem! - a local class that would be constructed within each std::list as the * allocator but really just delegates to ITEM_POOL */ class local_alloc { public : //!! I understand that I can't access ITEM_POOL from within a nested class like //!! this, that's really my question - can I get something along these lines to //!! work?? pointer allocate (size_t n) { return ( item_pool.allocate(n) ); } }; public : make_quadtree (): item_pool() // only construct 1 instance of ITEM_POOL per // MAKE_QUADTREE object { /* The kind of data structures - vectors of linked lists * The idea is that all of the linked lists should share a local pooled allocator */ std::vector<std::list<int, local_alloc>> lists; /* The actual operations - too complicated to show, but in general: * * - The vector LISTS is grown as a quadtree is built, it's size is the number of * quadtree "boxes" * * - Each element of LISTS (each linked list) represents the ID's of items * contained within each quadtree box (say they're xy points), as the quadtree * is grown a lot of ID pop/push-ing between lists occurs, hence the memory pool * is important for performance */ } }; So really my problem is that I'd like to have one memory pool instance per thread functor instance, but within each thread functor share the pool between multiple std::list objects.

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• Nested Transaction issues within custom Windows Service

  - by pdwetz

  I have a custom Windows Service I recently upgraded to use TransactionScope for nested transactions. It worked fine locally on my old dev machine (XP sp3) and on a test server (Server 2003). However, it fails on my new Windows 7 machine as well as on 2008 Server. It was targeting 2.0 framework; I tried targeting 3.5 instead, but it still fails. The strange part is really in how it fails; no exception is thrown. The service itself merely times out. I added tracing code, and it fails when opening the connection for Database lookup #2 below. I also enabled tracing for System.Transactions; it literally cuts out partway while writing the block for the failed connection. We ran a SQL trace, but only the first lookup shows up. I put in code traces, and it gets to the trace the line before the second lookup, but nothing after. I've had the same experience hitting two different SQL servers (both are SQL 2005 running on Server 2003). The connection string is utilizing a SQL account (not Windows integration). All connections are against the same database in this case, but given the nature of the code it is being escalated to MSDTC. Here's the basic code structure: TransactionOptions options = new TransactionOptions(); options.IsolationLevel = System.Transactions.IsolationLevel.ReadCommitted; using (TransactionScope scope = new TransactionScope(TransactionScopeOption.RequiresNew, options)) { // Database lookup #1 TransactionOptions options = new TransactionOptions(); options.IsolationLevel = Transaction.Current != null ? Transaction.Current.IsolationLevel : System.Transactions.IsolationLevel.ReadCommitted; using (TransactionScope scope = new TransactionScope(TransactionScopeOption.Required, options)) { // Database lookup #2; fails on connection.Open() // Database save (never reached) scope.Complete();<br/> } scope.Complete();<br/> } My local firewall is disabled. The service normally runs using Network Service, but I also tried my user account (same results). The short of it is that I use the same general technique widely in my web applications and haven't had any issues. I pulled out the code and ran it fine within a local Windows Form application. If anyone has any additional debugging ideas (or, even better, solutions) I'd love to hear them.

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• Remove links with Javascript

  - by Arlen Beiler

  How do I remove links from a webpage with Javascript. I am using Google Chrome. The code I tried is: function removehyperlinks() { try { alert(document.anchors.length); alert(document.getElementsByTagName('a')); for(i=0;i=document.anchors.length;i++) { var a = document.anchors[i]; a.outerHTML = a.innerHTML; var b = document.getElementsByTagName('a'); b[i].outerHTML = b[i].innerHTML; } } catch(e) { alert (e);} alert('done'); } Of course, this is test code, which is why I have the alerts and 2 things trying at the same time. The first alert returns "0" the second [Object NodeList] and the third returns "done". My html body looks like this: <body onload="removehyperlinks()"> <ol style="text-align:left;" class="messagelist"> <li class="accesscode"><a href="#">General information, Updates, &amp; Meetings<span class="extnumber">141133#</span></a> <ol> <li><a href="#">...</a></li> <li><a href="#">...</a></li> <li><a href="#">...</a></li> <li><a href="#">...</a></li> <li><a href="#">...</a></li> <li><a href="#">...</a></li> <li><a href="#">...</a></li> <li><a href="#">...</a></li> <li start="77"><a href="#"">...</a></li> <li start="88"><a href="#">...</a></li> <li start="99"><a href="#">...</a></li> </ol> </li> </ol> </body>

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• how to refactor user-permission system?

  - by John

  Sorry for lengthy question. I can't tell if this should be a programming question or a project management question. Any advice will help. I inherited a reasonably large web project (1 year old) from a solo freelancer who architected it then abandoned it. The project was a mess, but I cleaned up what I could, and now the system is more maintainable. I need suggestions on how to extend the user-permission system. As it is now, the database has a t_user table with the column t_user.membership_type. Currently, there are 4 membership types with the following properties: 3 of the membership types are almost functionally the same, except for the different monthly fees each must pay 1 of the membership type is a "fake-user" type which has limited access ( different business logic also applies) With regards to the fake-user type, if you look in the system's business logic files, you will see a lot of hard-coded IF statements that do something like if (fake-user) { // do something } else { // a paid member of type 1,2 or 3 // proceed normally } My client asked me to add 3 more membership types to the system, each of them with unique features to be implemented this month, and substantive "to-be-determined" features next month. My first reaction is that I need to refactor the user-permission system. But it concerns me that I don't have enough information on the "to-be-determined" membership type features for next month. Refactoring the user-permission system will take a substantive amount of time. I don't want to refactor something and throw it out the following month. I get substantive feature requests on a monthly basis that come out of the blue. There is no project road map. I've asked my client to provide me with a roadmap of what they intend to do with the new membership types, but their answer is along the lines of "We just want to do [feature here] this month. We'll think of something new next month." So questions that come to mind are: 1) Is it dangerous for me to refactor the user permission system not knowing what membership type features exist beyond a month from now? 2) Should I refactor the user permission system regardless? Or just continue adding IF statements as needed in all my controller files? Or can you recommend a different approach to user permission systems? Maybe role-based ? 3) Should this project have a road map? For a 1 year old project like mine, how far into the future should this roadmap project? 4) Any general advice on the best way to add 3 new membership types?

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• How do you remind your Scrum Product Owner about his promises/actions?

  - by Felix Ogg

  ** EDIT: Rephrased the question to re-focus ** Our Scrum team meets as seldomly as possible, but we meet with the product owner every chance we get. We track everyone's agreed action points (particularly theirs). We are 100% agile, but our product owner lives in traditional world, we remain off-site. We facilitate him in crossing over to our fast-paced world. There's not much wrong. The team and the PO are in good spirits. PO is present at every meeting and positively energized. Just imagine this person as a 70 year old, slow grandpa, who is forgetful, yet kind. In reality he isn't, but he is used to a working environment (public servants) that is much slooooower. Manyana-manyana etc. It is frustrating for my team to cooperate: PO lives in a non-prioritized environment, and everyone in it has learned the productivity-technique of NGTD (Not Getting Things Done). He WANTS to, it's just that he forgets or 'sinks' somewhere along the away. We have experimented with a text file, maintained by the Scrum master (low-tech), which he broadcasts by e-mail every day JIRA, our issue tracker. Turns out this is nice for programmers, but too steep for 'regular people' I Googled for Issue tracking webtools but came up empty handed: All tools are aimed at IT issue tracking, instead of meeting action point tracking/planning for mere mortals. I did find TODO-lists like RememberTheMilk, but they don't track comments, and - to be honest - I doubt we could get our product owner to use it (too complicated). We have three requirements: Register action points, assign to a team member and a deadline Offer anyone to 'comment' on progress of any action point Do not build our own tool from scratch We do not need: - impressive authorization models, - multi-project, - workflow, - crosslinking. Is there any trick/tool you use to assist your product owner 'fly' like the rest of the rest of the team? Communication before tools I agree with the general consensus that one should not try to apply technology to a communication problem, however in this case I am merely looking for a tool to save me time in setting up prioritized lists. I found www.thymer.com today, may be what I am looking for. The guys are cool. It is getting rather feature-bloated though.

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• highlight query string in more than one field using solr search feature

  - by Romi

  i am using solr indexes for showing my search results. to show serch results i am parsing json data received from solr. i am able to highlight a query string in search result but only in a single field. for this i set hl=true and hl.fl="field1". i did it as $.getJSON("http://192.168.1.9:8983/solr/db/select/?wt=json&&start=0&rows=100&q="+lowerCaseQuery+"&hl=true&hl.fl=description,name&hl.usePhraseHighlighter=true&sort=price asc&json.wrf=?", function(result){ var n=result.response.numFound var highlight = new Array(n); $.each(result.highlighting, function(i, hitem){ var match = hitem.text[0].match(/<em>(.*?)<\/em>/); highlight[i]=match[1]; }); $.each(newresult.response.docs, function(i,item){ var word=highlight[item["UID_PK"]]; var result = item.text[0].replace(new RegExp(word,'g'), '<em>' + word + '</em>'); }); for this json object is as : { "responseHeader": { "status": 0, "QTime": 32 }, "response": { "numFound": 21, "start": 0, "docs": [ { "description": "The matte finish waves on this wedding band contrast with the high polish borders. This sharp and elegant design was finely crafted in Japan.", "UID_PK": "8252", }, { "description": "This elegant ring has an Akoya cultured pearl with a band of bezel-set round diamonds making it perfect for her to wear to work or the night out.", "UID_PK": "8142", }, ] }, "highlighting": { "8252": { "description": [ " and <em>elegant</em> design was finely crafted in Japan." ] }, "8142": { "description": [ "This <em>elegant</em> ring has an Akoya cultured pearl with a band of bezel-set round diamonds making" ] }, } } Now if i want to highlight query string in two fields i did as hl=true hl.fl=descrption, name my json is as: { "responseHeader":{ "status":0, "QTime":16 }, "response":{ "numFound":1904, "start":0, "docs":[ { "description":"", "UID_PK":"7780", "name":[ "Diamond bracelet with Milgrain Bezel1" ] }, { "description":"This pendant is sure to win hearts. Round diamonds form a simple and graceful line.", "UID_PK":"8121", "name":[ "Heartline Diamond Pendant" ] }, "highlighting":{ "7780":{ "name":[ "<em>Diamond</em> bracelet with Milgrain Bezel1" ] }, "8121":{ "description":[ "This pendant is sure to win hearts. Round <em>diamonds</em> form a simple and graceful line." ], "name":[ "Heartline <em>Diamond</em> Pendant" ] } } } Now how should i parse it to get the result. suggest me some general technique, so if i want to highlight query in more fields then i could do so. Thanks

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• Design patterns and interview question

  - by user160758

  When I was learning to code, I read up on the design patterns like a good boy. Long after this, I started to actually understand them. Design discussions such as those on this site constantly try to make the rules more and more general, which is good. But there is a line, over which it becomes over-analysis starts to feed off itself and as such I think begins to obfuscate the original point - for example the "What's Alternative to Singleton" post and the links contained therein. http://stackoverflow.com/questions/1300655/whats-alternative-to-singleton I say this having been asked in both interviews I’ve had over the last 2 weeks what a singleton is and what criticisms I have of it. I have used it a few times for items such as user data (simple key-value eg. last file opened by this user) and logging (very common i'm sure). I've never ever used it just to have what is essentially global application data, as this is clearly stupid. In the first interview, I reply that I have no criticisms of it. He seemed disappointed by this but as the job wasn’t really for me, I forgot about it. In the next one, I was asked again and, as I wanted this job, I thought about it on the spot and made some objections, similar to those contained in the post linked to above (I suggested use of a factory or dependency injection instead). He seemed happy with this. But my problem is that I have used the singleton without ever using it in this kind of stupid way, which I had to describe on the spot. Using it for global data and the like isn’t something I did then realised was stupid, or read was stupid so didn’t do, it was just something I knew was stupid from the start. Essentially I’m supposed to be able to think of ways of how to misuse a pattern in the interview? Which class of programmers can best answer this question? The best ones? The medium ones? I'm not sure.... And these were both bright guys. I read more than enough to get better at my job but had never actually bothered to seek out criticisms of the most simple of the design patterns like this one. Do people think such questions are valid and that I ought to know the objections off by heart? Or that it is reasonable to be able to work out what other people who are missing the point would do on the fly? Or do you think I’m at least partially right that the question is too unsubtle and that the questions ought to be better thought out in order to make sure only good candidates can answer. PS. Please don’t think I’m saying that I’m just so clever that I know everything automatically - I’ve learnt the hard way like everyone else. But avoiding global data is hardly revolutionary.

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• Converting C source to C++

  - by Barry Kelly

  How would you go about converting a reasonably large (300K), fairly mature C codebase to C++? The kind of C I have in mind is split into files roughly corresponding to modules (i.e. less granular than a typical OO class-based decomposition), using internal linkage in lieu private functions and data, and external linkage for public functions and data. Global variables are used extensively for communication between the modules. There is a very extensive integration test suite available, but no unit (i.e. module) level tests. I have in mind a general strategy: Compile everything in C++'s C subset and get that working. Convert modules into huge classes, so that all the cross-references are scoped by a class name, but leaving all functions and data as static members, and get that working. Convert huge classes into instances with appropriate constructors and initialized cross-references; replace static member accesses with indirect accesses as appropriate; and get that working. Now, approach the project as an ill-factored OO application, and write unit tests where dependencies are tractable, and decompose into separate classes where they are not; the goal here would be to move from one working program to another at each transformation. Obviously, this would be quite a bit of work. Are there any case studies / war stories out there on this kind of translation? Alternative strategies? Other useful advice? Note 1: the program is a compiler, and probably millions of other programs rely on its behaviour not changing, so wholesale rewriting is pretty much not an option. Note 2: the source is nearly 20 years old, and has perhaps 30% code churn (lines modified + added / previous total lines) per year. It is heavily maintained and extended, in other words. Thus, one of the goals would be to increase mantainability. [For the sake of the question, assume that translation into C++ is mandatory, and that leaving it in C is not an option. The point of adding this condition is to weed out the "leave it in C" answers.]

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