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  • Where does the compiler store methods for C++ classes?

    - by Mashmagar
    This is more a curiosity than anything else... Suppose I have a C++ class Kitty as follows: class Kitty { void Meow() { //Do stuff } } Does the compiler place the code for Meow() in every instance of Kitty? Obviously repeating the same code everywhere requires more memory. But on the other hand, branching to a relative location in nearby memory requires fewer assembly instructions than branching to an absolute location in memory on modern processors, so this is potentially faster. I suppose this is an implementation detail, so different compilers may perform differently. Keep in mind, I'm not considering static or virtual methods here.

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  • Is it any loose coupling mechanism in Objective-C + Cocoa like C# delegates or C++Qt signals+slots?

    - by Eye of Hell
    Hello. For a large programs, the standard way to chalenge a complexity is to divide a program code into small objects. Most of the actual programming languages offer this functionality via classes, so is Objective-C. But after source code is separated into small object, the second challenge is to somehow connect them with each over. Standard approaches, supported by most languages are compositon (one object is a member field of another), inheritance, templates (generics) and callbacks. More cryptic techniques include method-level delagates (C#) and signals+slots (C++Qt). I like the delegates / signals idea, since while connecting two objects i can connect individual methods with each over, without objects knowing anything of each over. For C#, it will look like this: var object1 = new CObject1(); var object2 = new CObject2(); object1.SomethingHappened += object2.HandleSomething; In this code, is object1 calls it's SomethingHappened delegate (like a normal method call) the HandleSomething method of object2 will be called. For C++Qt, it will look like this: var object1 = new CObject1(); var object2 = new CObject2(); connect( object1, SIGNAL(SomethingHappened()), object2, SLOT(HandleSomething()) ); The result will be exactly the same. This technique has some advantages and disadvantages, but generally i like it more than interfaces since if program code base grows i can change connections and add new ones without creating tons of interfaces. After examination of Objective-C i havn't found any way to use this technique i like :(. It seems that Objective-C supports message passing perfectly well, but it requres for object1 to have a pointer to object2 in order to pass it a message. If some object needs to be connected to lots of other objects, in Objective-C i will be forced to give him pointers to each of the objects it must be connected. So, the question :). Is it any approach in Objective-C programming that will closely resemble delegate / signal+slot types of connection, not a 'give first object an entire pointer to second object so it can pass a message to it'. Method-level connections are a bit more preferable to me than object-level connection ^_^.

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  • What can't the NDK be used for?

    - by Android Eve
    From the official NDK site: The Android NDK... provides headers and libraries that allow you to build activities, handle user input, use hardware sensors, access application resources, and more, when programming in C or C++. If you write native code, your applications are still packaged into an .apk file and they still run inside of a virtual machine on the device. The fundamental Android application model does not change. Yet, it is always described as a companion tool to the Android SDK and as a toolset that allows to "implement parts of your applications using native-code languages such as C and C++". My understanding from this is that, unlike the Java based SDK, the NDK is not designed to implement certain parts of an Android application. Is this correct? If so, what parts doesn't the NDK allow implementing?

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  • Handler not yet determined error

    - by SourceC
    Hello, I don’t know anything about deploying a website, so I probably made some stupid mistake. Anyways, I opened IIS 7 manager, created new virtual directory ( via Add Application ) and pointed it to physical directory where Visual studio saved my Web project. But when I tried to request an .aspx page, browser reported the following error (I won’t post the whole error, but just the interesting bits): Handler: Not yet determined Config Error: Cannot read configuration file due to insufficient permissions Logon User: Not yet determined A) why is handler not yet determined? As far as I know, IIS7 does have Asp.Net handler registered?! B) Why wouldn’t IIS have sufficient permissions? Does that mean I should give IIS higher privileges? Or does Asp.Net runtime have insufficient permissions? C) Could the error also be due to the fact that perhaps it expected the user to authenticate itself? I’m assuming this due to Logon user not yet being determined? D) And finally, any ideas how to make it work? thanx

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  • SQL Query: Using IF statement in defining new field

    - by Tofig Hasanov
    I have a table with many fields and additionally several boolean fields (ex: BField1, BField2, BField3 etc.). I need to make a Select Query, which will select all fields except for boolean ones, and a new virtual field (ex: FirstTrueBool) whose value will equal to the name of the first TRUE Boolean Field. For ex: Say I have BField1 = False, BField2 = True, BField3 = true, BField4=false, in that case SQL Query should set [FirstTrueBool] to "BField2". Is that possible? Thank you in advance. P.S. I use Microsoft Access (MDB) Database and Jet Engine.

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  • Resizing Ubuntu x64 Server Partition with VirtualBox not reflected in OS

    - by daleyjem
    I've already resized my virtual disk with VirtualBox, but now need to extend the partition of my Ubuntu VM itself. I thought I was on my way with GParted live CD, but after I resize the "extended" filesystem partition, and then the child "lvm2 pv" filesystem partition to fill the unallocated space, df -h still shows the original disk size after I reboot into the VM. Any tips on this? I've scoured the webs tirelessly. Should I be resizing the boot (/dev/sda1) partition instead? Should I try to convert my lvm2 to ext4 or something? I'm lost on this. Note: VirtualBox hard disk is "dynamic". Specs: VBox 4.2.18 Ubuntu 12.04.2 amd64 Gparted 0.16.2-1b-i486

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  • Storing expression template functors

    - by UncaughtException
    Hello guys, at the moment I'm really interested in expression templates and want to code a library for writing and differentiating mathematical functions with a lambda-style syntax. At the moment, I'm able to write (_x * _x)(2); and get the correct result 4. But I would really like to do something like MathFunction f = _x * _x; f(2);, but I don't have any ideas on how to cope with the recursive expression templates on the right side. Is it possible to achieve this without using the 'auto'-Keyword instead of MathFunction or having to make the operator() virtual? Thanks for your help!

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  • Using vim, how do you quickly refresh a web page you're working on?

    - by aLostMonkey
    I've been using VIM for a few weeks now while messing with various web languages and I'm really enjoying it. I find it cumbersome having to tab or click into my browser and refresh the page to see the effect of a code change. It's even more annoying as I'm using Virtual Box and I tend to be working from PDF files on the host system so I have limited window space. Do you gurus have any fancy ways of doing this? I was wondering if it's possible to split the VIM workspace and have links/lynx in a window of its own or something to that effect?

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  • SELECT only a certain set of rows at a time

    - by prmatta
    I need to select data from one table and insert it into another table. Currently the SQL looks something like this: INSERT INTO A (x, y, z) SELECT x, y, z FROM B b WHERE ... However, the SELECT is huge, resulting in over 2 millions rows and we think it is taking up too much memory. Informix, the db in this case, runs out of virtual memory when the query is run. How would I go about selecting and inserting a set of rows (say 2000)? Given that I don't think there are any row ids etc.

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  • C++ Array of pointers: delete or delete []?

    - by Jasper
    Cosider the following code: class Foo { Monster* monsters[6]; Foo() { for (int i = 0; i < 6; i++) { monsters[i] = new Monster(); } } virtual ~Foo(); } What is the correct destructor? this: Foo::~Foo() { delete [] monsters; } or this: Foo::~Foo() { for (int i = 0; i < 6; i++) { delete monsters[i]; } } I currently have the uppermost constructor and everything is working okey, but of course I cannot see if it happens to be leaking... Personally, I think the second version is much more logical considering what I am doing. Anyway, what is the "proper" way to do this?

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  • MVVM Binding To Property == Null

    - by LnDCobra
    I want to show some elements when a property is not null. What is the best way of achieving this? The following is my ViewModel: class ViewModel : ViewModelBase { public Trade Trade { get { return _trade; } set { SetField(ref _trade, value, () => Trade); } } private Trade _trade; } ViewModelBase inherits INotifyPropertyChanged and contains SetField() The Following is the Trade class: public class Trade : INotifyPropertyChaged { public virtual Company Company { get { return _company; } set { SetField(ref _company, value, () => Company); } } private Company _company; ...... } This is part of my View.xaml <GroupBox Visibility="{Binding Path=Trade.Company, Converter={StaticResource boolToVisConverter}}" /> I would like this groupbox to show only if Trade.Company is not null (so when a user selects a company). Would I need to create a custom converter to check for null and return the correct visibility or is there one in .NET?

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  • Noob tab widget example not running

    - by michbeck
    hey all, i'm trying to reproduce the tabwidget example (http://developer.android.com/resources/tutorials/views/hello-tabwidget.html). i'm not really sure what's the problem, i've git no errors while compiling, but i cannot see the application on emulators screen :-/ would be excellent if maybe anyone could have a look at my classes and tell me what's my mistake? I've packed my project here: http://etanto.com/TabTest.zip thanx a lot in advance, folks! michbeck here's the console dump while the run: [2010-06-10 09:18:34 - TabTest] Launching a new emulator with Virtual Device 'Virtual1' [2010-06-10 09:18:35 - TabTest] New emulator found: emulator-5554 [2010-06-10 09:18:35 - TabTest] Waiting for HOME ('android.process.acore') to be launched... [2010-06-10 09:19:05 - TabTest] WARNING: Application does not specify an API level requirement! [2010-06-10 09:19:05 - TabTest] Device API version is 8 (Android 2.2) [2010-06-10 09:19:05 - TabTest] HOME is up on device 'emulator-5554' [2010-06-10 09:19:05 - TabTest] Uploading TabTest.apk onto device 'emulator-5554' [2010-06-10 09:19:05 - TabTest] Installing TabTest.apk... [2010-06-10 09:19:22 - TabTest] Success! [2010-06-10 09:19:22 - TabTest] \TabTest\bin\TabTest.apk installed on device [2010-06-10 09:19:22 - TabTest] Done!

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  • What frameworks should we consider for a custom web application?

    - by justkevin
    A client is looking for a custom web application, which will eventually include lots of interconnected components, but the main features are: Subscription based membership as well as virtual/digital product sales Members have their own public web cookie-cutter directories (e.g., storefronts, pages, etc.) and personal member admin area. Site administrators will need both common tools (member admin, password changes, etc.) and custom tools that can be readily developed or integrated with 3rd party solutions. What frameworks should we be looking at? PHP/MySQL is preferable unless something really outstanding is available in another stack.

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  • Running Firefox in the Windows service mode

    - by Leonid
    I'm writing a server running as a Windows service that by request invokes Firefox to generate a pdf snapshot of a webpage. I know it is a bad idea to run a GUI program in service mode, but the server nature of my program restricts from running it in the user mode. Running a user-level 'proxy' also is not an option, since there might be no interactive user logged-in on the machine with the server running. In my experiments Firefox successfully produced pdf when the service was running under a user account that was already logged-in. Obviously it didn't work in other cases: for Local System and user accounts that weren't logged-in. Under LocalSystem with 'Allow service to interact with desktop' option enabled I could see the Firefox started that reports that it's unable to find a printer. Since it wouldn't be practical to require an opened user session for the pdf server to run, is there any workaround for this except running the whole thing from a virtual machine?

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  • save state of external running program

    - by SuitUp
    Hi, my goal is to save state of running process and later start from this point. This is not necessary need to be state from this exact moment, let's say save after 5 seconds is good too. Problem is, i can't alter in code of this external program, i am even don't aware of it's architecture. I have resources to save whole program to disk from memory, but i need some tips, where to start. I can't use any VM like Virtual Box to save state of whole operating system, and program can be written in c++ or c or c#...

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  • OpenGL "out of memory" on glReadPixels()

    - by spurserh
    Hello, I am running into an "out of memory" error from OpenGL on glReadPixels() under low-memory conditions. I am writing a plug-in to a program that has a robust heap mechanism for such situations, but I have no idea whether or how OpenGL could be made to use it for application memory management. The notion that this is even possible came to my attention through this [albeit dated] thread on a similar issue under Mac OS X: http://lists.apple.com/archives/Mac-opengl/2001/Sep/msg00042.html I am using Windows XP, and have seen it on multiple NVidia cards. I am also interested in any work-arounds I might be able to relay to users (the thread mentions "increasing virtual memory"). Thanks, Sean

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  • Is typeid of type name always evaluated at compile time in c++ ?

    - by cyril42e
    I wanted to check that typeid is evaluated at compile time when used with a type name (ie typeid(int), typeid(std::string)...). To do so, I repeated in a loop the comparison of two typeid calls, and compiled it with optimizations enabled, in order to see if the compiler simplified the loop (by looking at the execution time which is 1us when it simplifies instead of 160ms when it does not). And I get strange results, because sometimes the compiler simplifies the code, and sometimes it does not. I use g++ (I tried different 4.x versions), and here is the program: #include <iostream> #include <typeinfo> #include <time.h> class DisplayData {}; class RobotDisplay: public DisplayData {}; class SensorDisplay: public DisplayData {}; class RobotQt {}; class SensorQt {}; timespec tp1, tp2; const int n = 1000000000; int main() { int avg = 0; clock_gettime(CLOCK_REALTIME, &tp1); for(int i = 0; i < n; ++i) { // if (typeid(RobotQt) == typeid(RobotDisplay)) // (1) compile time // if (typeid(SensorQt) == typeid(SensorDisplay)) // (2) compile time if (typeid(RobotQt) == typeid(RobotDisplay) || typeid(SensorQt) == typeid(SensorDisplay)) // (3) not compile time ???!!! avg++; else avg--; } clock_gettime(CLOCK_REALTIME, &tp2); std::cout << "time (" << avg << "): " << (tp2.tv_sec-tp1.tv_sec)*1000000000+(tp2.tv_nsec-tp1.tv_nsec) << " ns" << std::endl; } The conditions in which this problem appear are not clear, but: - if there is no inheritance involved, no problem (always compile time) - if I do only one comparison, no problem - the problem only appears only with a disjunction of comparisons if all the terms are false So is there something I didn't get with how typeid works (is it always supposed to be evaluated at compilation time when used with type names?) or may this be a gcc bug in evaluation or optimization? About the context, I tracked down the problem to this very simplified example, but my goal is to use typeid with template types (as partial function template specialization is not possible). Thanks for your help!

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  • Hudson build fails when a user logs out of RDP session

    - by sjohnston
    We are using Hudson to build mixed C++/Java projects with an Ant script. It is running in Tomcat 6, on a Win XP virtual machine. I have noticed recently that when a user logs off the machine (from a remote desktop session), builds that are currently running tend to suddenly fail without an error message. Has anyone encountered anything similar or have an idea what might be causing this effect? I can post additional information about our setup if needed, I'm just not sure what's relevant in this case.

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  • c++ polymorphism and other function question

    - by aharont
    i have got this code: class father{ public: virtual void f() { cout<<1;} }; class son:public father{ public: void f() {cout<<2;} }; void test (father x){x.f();} int main(){ son s; test(s); } the question says: the output is '1', what is the rule about polymorphism that the programmer forgot and how can i fix it so the output would be '2'? there is another rule that the programmer forgot when he wrote the father class, and he need to add an empty function to avoid problems from other sons of the father class. what is the rule and what is the missing function? another question write the g function so the next code would run with no crashes int x=11; g(x)=22;

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  • (C#) How do you de-elevate permissions for a child process

    - by Davy8
    I know how to launch a process with Admin privileges from a process using: proc.StartInfo.UseShellExecute = true; proc.StartInfo.Verb = "runas"; where proc is a System.Diagnostics.Process. But how does one do the opposite? If the process you're in is already elevated, how do you launch the new process without admin privileges? More accurately, we need to launch the new process with the same permission level as Windows Explorer, so no change if UAC is diabled, but if UAC is enabled, but our process is running elevated, we need to perform a certain operation un-elevated because we're creating a virtual drive and if it's created with elevated permissions and Windows explorer is running unelevated it won't show up. Feel free to change the title to something better, I couldn't come up with a good description

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  • How to OrderBy on a generic IEnumerable (IEnumerable<T>) using LINQ in C#?

    - by Jeffrey
    In my generic repository I have below method: public virtual IEnumerable<T> GetAll<T>() where T : class { using (var ctx = new DataContext()) { ctx.ObjectTrackingEnabled = false; var table = ctx.GetTable<T>().ToList().AsReadOnly(); return table; } } T is a Linq to Sql class and I want to be able to OrderBy on a particular property. Say if T has property name "SortOrder" then do OrderBy on this property. But I am not sure how I can achieve this. So I need some helps. Thank you!

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  • Detect touch Cocos2d-x

    - by James Dunay
    I'm using Cocos2d-x and trying to detect touches in my HelloWorld project. Though I'm having no luck. .h class HelloWorld : public CCLayer{ private: CCSpriteBatchNode * _batchNode; CCSprite *_turkey; virtual void ccTouchesBegan(cocos2d::CCSet* touches, cocos2d::CCEvent* event); .ccp void HelloWorld::ccTouchesBegan(cocos2d::CCSet* touches, cocos2d::CCEvent* event){ CCLog("this"); } but the thing is that when I click the screen 'this' never shows up in the log. What am i missing here? thanks!

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  • silverlight application deployment over IIS

    - by Piyush
    I have created an silverlight application (i have not selected my application to be hosted from another web application). Now I created a simple hello world page. I created virtual directory of my silverlight project in IIS for application hosting. 4. When I browse MainPage.xaml in loaclhost, it is not running. I think I shoul run the .xap file to host my application but I dont know haw??? OR Is it necessary to host a silverlight application from a .aspx page??

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  • Vector of objects

    - by Paul
    I've got a abstract class class A { public: virtual void somefunction() = ; }; and some different classes that inherit this class: class Ab { public: void somefunction(); }; etc. I want to make a vector containing some objects of these classes (how many depends on input parameters) so I can access these easily later. However I'm a bit lost on how to do this. My best idea is vector<A> *objectsVector; Ab AbObject; objectsVector.push_back(AbObject); However this gives me a huge amout of errors from various .h files in /usr/include/c++ How should i solve this?

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  • Why is my Type.GetFields(BindingFlags.Instance|BindingFlags.Public) not working?

    - by granadaCoder
    My code can see the non-public members, but not the public ones. Why? FieldInfo[] publicFieldInfos = t.GetFields(BindingFlags.Instance | BindingFlags.Public); is returning nothing. Note: I'm trying to get at the properties on the abstract class as well as the concrete class. (And read the attributes as well). The MSDN example works with the 2 flags (BindingFlags.Instance | BindingFlags.Public) but my mini inheritance example below does not. private void RunTest1() { try { textBox1.Text = string.Empty; Type t = typeof(MyInheritedClass); //Look at the BindingFlags *** NonPublic *** int fieldCount = 0; while (null != t) { fieldCount += t.GetFields(BindingFlags.Instance | BindingFlags.NonPublic).Length; FieldInfo[] nonPublicFieldInfos = t.GetFields(BindingFlags.Instance | BindingFlags.NonPublic); foreach (FieldInfo field in nonPublicFieldInfos) { if (null != field) { Console.WriteLine(field.Name); } } t = t.BaseType; } Console.WriteLine("\n\r------------------\n\r"); //Look at the BindingFlags *** Public *** t = typeof(MyInheritedClass); FieldInfo[] publicFieldInfos = t.GetFields(BindingFlags.Instance | BindingFlags.Public); foreach (FieldInfo field in publicFieldInfos) { if (null != field) { Console.WriteLine(field.Name); object[] attributes = field.GetCustomAttributes(t, true); if (attributes != null && attributes.Length > 0) { foreach (Attribute att in attributes) { Console.WriteLine(att.GetType().Name); } } } } } catch (Exception ex) { ReportException(ex); } } private void ReportException(Exception ex) { Exception innerException = ex; while (innerException != null) { Console.WriteLine(innerException.Message + System.Environment.NewLine + innerException.StackTrace + System.Environment.NewLine + System.Environment.NewLine); innerException = innerException.InnerException; } } public abstract class MySuperType { public MySuperType(string st) { this.STString = st; } public string STString { get; set; } public abstract string MyAbstractString { get; set; } } public class MyInheritedClass : MySuperType { public MyInheritedClass(string ic) : base(ic) { this.ICString = ic; } [Description("This is an important property"), Category("HowImportant")] public string ICString { get; set; } private string _oldSchoolPropertyString = string.Empty; public string OldSchoolPropertyString { get { return _oldSchoolPropertyString; } set { _oldSchoolPropertyString = value; } } [Description("This is a not so importarnt property"), Category("HowImportant")] public override string MyAbstractString { get; set; } }

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