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• Is there a way to cause a new C++ class instance to fail, if certain conditions in the contructor ar

  - by Jim Fell

  As I understand it, when a new class is instantiated in C++, a pointer to the new class is returned, or NULL, if there is insufficient memory. I am writing a class that initializes a linked list in the constructor. If there is an error while initializing the list, I would like the class instantiator to return NULL. For example: MyClass * pRags = new MyClass; If the linked list in the MyClass constructor fails to initialize properly, I would like pRags to equal NULL. I know that I can use flags and additional checks to do this, but I would like to avoid that, if possible. Does anyone know of a way to do this? Thanks.

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• iPhone - How to use #define in Universal app

  - by Satyam svv

  I'm creating universal app that runs oniphone and ipad. I'm using #define to create CGRect. And I want to use two different #define - one for iPhone and one for iPad. How can I declare them so that correct one will be picked by universal app.......... I think I've to update little more description to avoid confusion. I've a WPConstants.h file where I'm declaring all the #define as below #define PUZZLE_TOPVIEW_RECT CGRectMake(0, 0, 480, 100) #define PUZZLE_MIDDLEVIEW_RECT CGRectMake(0, 100, 480, 100) #define PUZZLE_BOTTOMVIEW_RECT CGRectMake(0, 200, 480, 100) The above ones are for iphone. Similarly for iPad I want to have different #define How can I proceed further?

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• Cakephp ajax Autocomplete not working

  - by Vijay Kumbhar

  Hello All, I am using ajax autocomplete in my application, but it is not giving the output. Ajax request to the desired function goes but it is not giving back any response, it is blank. I am also using jquery but it is used for other effects. i added jquery no conflict to avoid the prototype & jquery conflicts. I have tried other ajax helper methods like obeserverfield, it is working fine & returning the proper response, but when i use autocomplete it fails Can anybody help me ..........

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• How does compiling circular dependencies work?

  - by Fabio F.

  I've made the example in Java but I think (not tested) that it works in other (all?) languages. You have 2 files. First, M.java: public class MType { XType x; MType() {x = null;} } Second, another file (in the same directory), XType.java: public class XType { MType m; public XType(MType m) {this.m = m;} } Ok it's bad programming, but if you run javac XType it compiles: compiles even MType because XType needs it. But ... MType needs XType ... how does that work? How does the compiler know what is happening? Probably this is a stupid question, but I would like to know how the compiler (javac or any other compilers you know) manages that situation, not how to avoid it. I'm asking because i'm writing a precompiler and I would like to manage that situation.

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• Android how do I wait until a service is actually connected?

  - by Ryan

  I have an Activity calling a Service defined in IDownloaderService.aidl: public class Downloader extends Activity { IDownloaderService downloader = null; // ... In Downloader.onCreate(Bundle) I tried to bindService Intent serviceIntent = new Intent(this, DownloaderService.class); if (bindService(serviceIntent, sc, BIND_AUTO_CREATE)) { // ... and within the ServiceConnection object sc I did this public void onServiceConnected(ComponentName name, IBinder service) { Log.w("XXX", "onServiceConnected"); downloader = IDownloaderService.Stub.asInterface(service); // ... By adding all kinds of Log.xx I found that the code after if(bindService(...)) actually goes BEFORE ServiceConnection.onServiceConnected is being called - that is, when downloader is still null - which gets me into trouble. All the samples in ApiDemos avoid this timing problem by only calling services when triggered by user actions. But what should I do to right use this service after bindService succeeds? How can I wait for ServiceConnection.onServiceConnected being called reliably?

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• Strategy for Storing Multiple Nullable Booleans in SQL

  - by Eric J.

  I have an object (happens to be C#) with about 20 properties that are nullable booleans. There will be perhaps a few million such objects persisted to a SQL database (currently SQL Server 2008 R2, but MySQL may need to be supported in the future). The instances themselves are relatively large because they contain about a paragraph of text as well as some other unrelated properties. For a given object instance, most of the properties will be null most of the time. When users search for instances of such objects, they will select perhaps 1-3 of the nullable boolean properties and search for instances where at least one of those 1-3 properties is non-null (OR search). My first thought is to persist the object to a single table with nullable BIT columns representing the nullable boolean properties. However, this strategy will require one index per BIT column to avoid performing a table scan when searching. Further, each index would not be particularly selective since there are only three possible values per index. Is there a better way to approach this problem?

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• How to handle dependency files in a cross-platform manner?

  - by Brian Knoblauch

  I'm working on updating an old app. It has some dependency files that live in the same directory as the app. Obviously this broke when Windows Vista came out (since it violates the API and Vista/7 now enforce that (XP didn't)). Ideally, I'd like to avoid hardcoding anything into the app for just Windows. I can live with that if I have to though. I've already been down that path with pulling the APPDATA and LOCALAPPDATA environment variables, but that doesn't help any since they just give you the current user area... I need these to live somewhere accessible for all users, and I'd like to obey the Windows API expectations that they go into the all user appdata area. Suggestions?

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• Rails Variable across all controller actions

  - by bob

  Hello, This should be a very simple rails question. I have a variable like the following. @administration = Administration.first I want this variable to be accessible through every controller action across all my controllers so for example if I have a Product controller and inside of it I have the usual CRUD actions, I want the @administration variable as defined above to be put into all the CRUD actions. (It would not be needed in destroy or create or update). I have many controllers throughout my project and I was wondering if there is an easier way than adding it manually through all of the actions that I want it in. I tried a global variable $administration = Administration.first but I run into an issue where it is not updated when I update the actual content of the Administration.first table. Also, I would like to avoid global variables. Any help would be much appreciated. Thanks! :)

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• Javascript & jquery : Unable to increment within a form

  - by Daniyal

  I got a simple increment function like this: $(function(){ $("#inc").click(function(){ var value = parseInt($(":text[name='ice_id']").val()) + 1; $(":text[name='ice_id']").val(value); }); $("#dec").click(function(){ var value = parseInt($(":text[name='ice_id']").val()) - 1; $(":text[name='ice_id']").val(value); }); }); the ice_id text field is embedded within a form <form id="masterSubmit" name="masterSubmit" action="" method="post"> <td><input id="ice_id" type="text" name="ice_id" size="16" maxlength="15"></td> </form> When I try now to increment , it successfully increments a number, but shows the following weird behavior: It 'refreshes' the site, so that the content of the text field is gone. This behavior disappears, if I comment out the form tags ...unfortunately the form tags are required for an AJAX-submit. Are there any ways to avoid this problem? Thanks in advance for any hints and best regards Daniyal

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• Is there any way to store full size image returned from camera activity in internal memory ?

  - by SimpleGuy

  I am using Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE); intent.putExtra(MediaStore.EXTRA_OUTPUT,Uri.fromFile(externalFileObj)); intent to call default camera activity. To get full image you need to specify intent.putExtra(). But this always requires URI that works only for external storage files. I tried to create a temp.jpg image in internal memory and pass its URI Uri.fromFile(new File(getFilesDir() + "/temp.jpg")); but the camera activity won't return back after the image is captured. So there is no way to get Full size image from default camera application in our activity without using any external storage ? Assuming that the device do not have SD card or currently in use is there no way I can avoid using it ? Yes I know we can create our own camerapreview surface but I want to use the default camera application as it is natural with many more options. Thanks.

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• Syncronizing indices of function pointer table to table contents

  - by Thomas Matthews

  In the embedded system I'm working on, we are using a table of function pointers to support proprietary Dynamic Libraries. We have a header file that uses named constants (#define) for the function pointer indices. These values are used in calculating the location in the table of the function's address. Example: *(export_table.c)* // Assume each function in the table has an associated declaration typedef void (*Function_Ptr)(void); Function_Ptr Export_Function_Table[] = { 0, Print, Read, Write, Process, }; Here is the header file: *export_table.h* #define ID_PRINT_FUNCTION 1 #define ID_READ_FUNCTION 2 #define ID_WRITE_FUNCTION 3 #define ID_PROCESS_FUNCTION 4 I'm looking for a scheme to define the named constants in terms of their location in the array so that when the order of the functions changes, the constants will also change. (Also, I would like the compiler or preprocessor to calculate the indices to avoid human mistakes like typeo's.)

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• How to Execute Base Class's Method Before Implementors's Method?

  - by DaveDev

  I have the following page public partial class GenericOfflineCommentary : OfflineFactsheetBase { } where OfflineFactsheetBase is defined as public class OfflineFactsheetBase : System.Web.UI.Page { public OfflineFactsheetBase() { this.Load += new EventHandler(this.Page_Load); this.PreInit += new EventHandler(this.Page_PreInit); } protected void Page_PreInit(object sender, EventArgs e) { if (Request.QueryString["data"] != null) { this.PageData = StringCompressor.DecompressString(Request.QueryString["data"]); this.ExtractPageData(); } } } OfflineFactsheetBase has the following virtual method: public virtual void ExtractPageData() { // get stuff relevant to all pages that impmement OfflineFactsheetBase } which is implemented in all pages that impmement OfflineFactsheetBase as follows: public partial class GenericOfflineCommentary : OfflineFactsheetBase { public override void ExtractPageData() { // get stuff relevant to an OfflineCommentary page. } } Currently, only GenericOfflineCommentary's ExtractPageData() is firing. How can I modify this to first run OfflineFactsheetBase's ExtractPageData() and then GenericOfflineCommentary's? edit: I'm trying to avoid having to call base.ExtractPageData() in every implementor. Is this possible?

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• Detect if an assembly is available

  - by jgaa

  I'm implementing an installer in Java, that is supposed to download and install an application for non-privileged users in Windows (from XP and up). The application is written in C++, and depend on the usual VC runtime-libraries (msvcm90.dll and friends). In order to save bandwidth, I want to avoid downloading the VC redistributables if they already are available for the user. I do however have a problem finding a reliable method to detect if an assembly is installed. If the assembly is missing, I will deploy it as described here: http://msdn.microsoft.com/en-us/library/ms235291%28VS.80%29.aspx So the question is simply how to detect if a (any) assembly is installed on the machine. It's no requirement that this can be done from Java. I can easily write a small probe in C++ and link it statically for the task. jgaa

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• Why Solr admin query page interprets UTF-8 as ISO-8859-1

  - by Scott Chu

  I deploy a war to my Tomcat 6.0.35 on Win7 64bit and when I use full-interface query page (I mean form.jsp) in Solr Admin to query 2 Chinese character (say it's C1C2) , the debug info shows: <lst name="debug"> <str name="rawquerystring">æ°è</str> <str name="querystring">æ°è</str> <str name="parsedquery">NEWSID:æ°è</str> <str name="parsedquery_toString">NEWSID:æ°è</str> ... You can see C1C2 becomes æ°è. I deploy same war file to Tomcat on Linux or on another Win7 64bit of my colleagues' computer, the encoding acts well. Does anyone know why and how can I avoid this problem? Thanks in advance!

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• Hibernate Unit tests - Reset schema

  - by Marco

  Hi, I'm testing the CRUD operations of my DAOs in JUnit tests. When i execute the single test, Hibernate always resets the schema and populates the DB in a known state. But when i execute multiple tests in a row, Hibernate resets the schema once, and then the data is accumulated during the execution of the tests. This is an unexpected behavior, so I'd like to add in the @Before method of the tests a function that explicitly resets the schema to avoid the pesistence of side data created by previous tests during the execution chain. Any tips? Thanks

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• Is it considered bad practice to have ViewModel objects hold the Dispatcher?

  - by stiank81

  My WPF application is structured using the MVVM pattern. The ViewModels will communicate asynchronously with a server, and when the requested data is returned a callback in the ViewModel is triggered, and it will do something with this data. This will run on a thread which is not the UI Thread. Sometimes these callbacks involve work that needs to be done on the UI thread, so I need the Dispatcher. This might be things such as: Adding data to an ObservableCollection Trigger Prism commands that will set something to be displayed in the GUI Creating WPF objects of some kind. I try to avoid the latter, but the two first points here I find to be reasonable things for ViewModels to do. So; is it okay to have ViewModels hold the Dispatcher to be able to Invoke commands for the UI thread? Or is this considered bad practice? And why?

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• Fatal error: Cannot use string offset as an array

  - by learner

  Array ( [0] = Array ( [auth_id] = 1 [auth_section] = Client Data Base [auth_parent_id] = 0 [auth_admin] = 1 [sub] = Array ( [0] = Array ( [auth_id] = 2 [auth_section] = Client Contact [auth_parent_id] = 1 [auth_admin] = 1 ) ) ) [1] => Array ( [auth_id] => 6 [auth_section] => All Back Grounds [auth_parent_id] => 0 [auth_admin] => ,4 [sub] => Array ( [0] => Array ( [auth_id] => 7 [auth_section] => Edit Custom [auth_parent_id] => 6 [auth_admin] => 1 ) ) ) [2] => Array ( [auth_id] => 20 [auth_section] => Order Mail [auth_parent_id] => 0 [auth_admin] => 1 [sub] => ) } When I process the sub inner array it shows this error how can I avoid that :)

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• Preprocessor directive to test if this is C or C++

  - by Collin

  I'm trying to find a standard macro which will test whether a header file is being compiled as C or as C++. The purpose of this is that the header may be included by either C or C++ code, and must behave slightly differently depending on which. Specifically: In C, I need this to be the code: extern size_t insert (const char*); In C++, I need this to be the code: extern "C" size_t insert (const char*); Additionally, is there a way to avoid putting #ifdef's around every declaration in the header?

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• Rails has_one vs belongs_to semantics

  - by Anurag

  I have a model representing a Content item that contains some images. The number of images are fixed as these image references are very specific to the content. For example, the Content model refers to the Image model twice (profile image, and background image). I am trying to avoid a generic has_many, and sticking to multiple has_one's. The current database structure looks like: contents - id:integer - integer:profile_image_id - integer:background_image_id images - integer:id - string:filename - integer:content_id I just can't figure out how to setup the associations correctly here. The Content model could contain two belongs_to references to an Image, but that doesn't seem semantically right cause ideally an image belongs to the content, or in other words, the content has two images. This is the best I could think of (by breaking the semantics): class Content belongs_to :profile_image, :class_name => 'Image', :foreign_key => 'profile_image_id' belongs_to :background_image, :class_name => 'Image', :foreign_key => 'background_image_id' end Am I way off, and there a better way to achieve this association?

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• Defining multiple VBA objects within one function or sub-routine?

  - by Harokitty

  I have the following VBA code: Option Explicit Private a(2) as Double Private b(2) as Double Public Function Hello(X1 As Double, X2 As Double) As Double a(1) = X1 + X2 a(2) = X1/X2 b(1) = X1 b(2) = X2^2 Hello = a(1)+a(2)+b(1)+b(2) End Function Within the function Hello I have defined a(1),a(2),b(1),b(2). However, I want to make some function or sub-routine that accepts X1 and X2 as arguments and spits out the values for a(1),a(2),b(1),b(2). This is because I use the above definitions for a(1),a(2),b(1),b(2) in about 20 functions in my module and would like to avoid having to do the following in each function that I use thesis in: a(1) = X1 + X2 a(2) = X1/X2 b(1) = X1 b(2) = X2^2

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• Creating and releasing objects in the same method, while using self as delegate

  - by user200341

  In objective-c you are responsible for releasing objects you allocate, but what happens when you allocate an object in a method, assign self as the objects delegate, and then release the object. The callbacks from the newly created (and released) object fails at this point, or rather, doesn't happen. - (void)doSomething { MyObj *myObj = [[MyObj alloc] init]; myObj.delegate = self; [myObj performOperation]; [myObj release]; } - (void)callbackMethodFromMyObj:(NSString *)message { NSLog(message); } I can't release the object until the callback has occurred, and I can't avoid releasing the object in the same method that creates it (because it exists outside the scope). One way of doing it would be to pass the object along in the call-back and release it in the callback, but is this the right way to go about this?

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• Is shortening properties names worth it?

  - by raam86

  in how to node Blog rolling with node.js and mongoDB the author mentions it's a good idea to shorten proprieties names: ....oft-reported issue with mongoDB is the size of the data on the disk... each and every record stores all the field-names .... This means that it can often be more space-efficient to have properties such as 't', or 'b' rather than 'title' or 'body', however for fear of confusion I would avoid this unless truly required! I am aware of solutions of how to do it I am more intrested in when is it truly required?

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• Get previous element in IObservable without re-evaluating the sequence

  - by dcstraw

  In an IObservable sequence (in Reactive Extensions for .NET), I'd like to get the value of the previous and current elements so that I can compare them. I found an example online similar to below which accomplishes the task: sequence.Zip(sequence.Skip(1), (prev, cur) => new { Previous = prev, Current = cur }) It works fine except that it evaluates the sequence twice, which I would like to avoid. You can see that it is being evaluated twice with this code: var debugSequence = sequence.Do(item => Debug.WriteLine("Retrieved an element from sequence")); debugSequence.Zip(debugSequence.Skip(1), (prev, cur) => new { Previous = prev, Current = cur }).Subscribe(); The output shows twice as many of the debug lines as there are elements in the sequence. I understand why this happens, but so far I haven't found an alternative that doesn't evaluate the sequence twice. How can I combine the previous and current with only one sequence evaluation?

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• What is tha CAUSE of Error 523 and Error 200 in Blackberry handhelds

  - by voipsecuritydigest.com

  I'm Blackberry developer, customers using my application experiencing Error 523 and Error 200. Remedies to those errors are in first case - remove application, my application. In second case totally reload OS! This is very bad, and customers blame me! But this is I don't do anything illegal to make blackberry crash. I just used a lot of memory, which is obvious because customer want that. Everywhere including Blackberry knowledge base people talking how to fix the problem, which may happened to everybody using application from well known brands, for example Yahoo! finances. But nobody explains what is the mechanism behind this, and if it is possible to avoid the problem. I would like to know what is that CAUSE of Error 523 and Error 200?

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• Mono on OS X Compatible with MSVC 2010 peers?

  - by Chris

  I'm to begin .NET development at work but have the option of using MonoDevelop/Mono on OS X instead of MSVC 2010 on Windows and would prefer it because of my familiarity with OS X. We are likely going to use a number of popular frameworks, such as NHibernate and Castle DI - my question to those of you familiar with .NET development and Mono: will I be at much of a disadvantage? Are there strong incompatibilities or, with some "paper cuts", the two systems are roughly compatible? Again, my colleagues will be using MSVC 2010 and we intend on working on the same codebases together. Thanks for any insight you can give to this .NET newbie. EDIT: I should note I'll primarily be doing development with MVC 2, which I understand does work with Mono, and will have some leeward in choosing frameworks, i.e. I can avoid highly incompatible frameworks.

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