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• `enable_shared_from_this` has a non-virtual destructor

  - by Shtééf

  I have a pet project with which I experiment with new features of the upcoming C++0x standard. While I have experience with C, I'm fairly new to C++. To train myself into best practices, (besides reading a lot), I have enabled some strict compiler parameters (using GCC 4.4.1): -std=c++0x -Werror -Wall -Winline -Weffc++ -pedantic-errors This has worked fine for me. Until now, I have been able to resolve all obstacles. However, I have a need for enable_shared_from_this, and this is causing me problems. I get the following warning (error, in my case) when compiling my code (probably triggered by -Weffc++): base class ‘class std::enable_shared_from_this<Package>’ has a non-virtual destructor So basically, I'm a bit bugged by this implementation of enable_shared_from_this, because: A destructor of a class that is intended for subclassing should always be virtual, IMHO. The destructor is empty, why have it at all? I can't imagine anyone would want to delete their instance by reference to enable_shared_from_this. But I'm looking for ways to deal with this, so my question is really, is there a proper way to deal with this? And: am I correct in thinking that this destructor is bogus, or is there a real purpose to it?

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• how to write binary copy of structure array to file

  - by cerr

  I would like to write a binary image of a structure array to a binary file. I have tried this so far: #include <stdio.h> #include <string.h> #define NUM 256 const char *fname="binary.bin"; typedef struct foo_s { int intA; int intB; char string[20]; }foo_t; void main (void) { foo_t bar[NUM]; bar[0].intA = 10; bar[0].intB = 999; strcpy(bar[0].string,"Hello World!"); Save(bar); printf("%s written succesfully!\n",fname); } int Save(foo_t* pData) { FILE *pFile; int ptr = 0; int itr = 0; pFile = fopen(fname, "w"); if (pFile == NULL) { printf("couldn't open %s\n", fname); return; } for (itr = 0; itr<NUM; itr++) { for (ptr=0; ptr<sizeof(foo_t); ptr++) { fputc((unsigned char)*((&pData[itr])+ptr), pFile); } fclose(pFile); } } but the compiler is saying aggregate value used where an integer was expected fputc((unsigned char)*((&pData[itr])+ptr), pFile); and I don't quite understand why, what am I doing wrong? Thanks!

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• Problem with inner classes of the same name in Visual C++

  - by starblue

  I have a problem with Visual C++, where apparently inner classes with the same name but in different outer classes are confused. The problem occurs for two layers, where each layer has a listener interface as an inner class. B is a listener of A, and has its own listener in a third layer above it (not shown). The structure of the code looks like this: A.h class A { class Listener { Listener(); virtual ~Listener() = 0; } [...] } B.h class B : public A::Listener { class Listener { Listener(); virtual ~Listener() = 0; } [...] } B.cpp B::Listener::Listener() {} B::Listener::~Listener() {} I get the error B.cpp(49) : error C2509: '{ctor}' : member function not declared in 'B' The C++ compiler for Renesas sh2a has no problem with this, but then it is more liberal than Visual C++ in some other respects, too. If I rename the listener interfaces to have different names the problem goes away, but I'd like to avoid that (the real class names instead of A or B are rather long). Is what I'm doing correct C++, or is the complaint by Visual C++ justified? Is there a way to work around this problem without renaming the listener interfaces?

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• Link Button on asp.net user control not firing

  - by andyriome

  Hi I have a user control, which is added to another user control. The nested user control is built up of a gridview, an image button and a link button. The nested user control is added to the outer control as a collection object based upon the results bound to the gridview. The problem that I have is that my link button doesn't work. I click on it and the event doesn't fire. Even adding a break point was not reached. As the nested user control is added a number of times, I have set image button to have unique ids and also the link button. Whilst image button works correctly with its java script. The link button needs to fire an event in the code behind, but despite all my efforts, I can't make it work. I am adding the link button to the control dynamically. Below is the relevant code that I am using: public partial class ucCustomerDetails : System.Web.UI.UserControl { protected override void CreateChildControls( ) { base.CreateChildControls( ); string strUniqueID = lnkShowAllCust.UniqueID; strUniqueID = strUniqueID.Replace('$','_'); this.lnkShowAllCust.ID = strUniqueID; this.lnkShowAllCust.Click += new EventHandler(this.lnkShowAllCust_Click); this.Controls.Add(lnkShowAllCust); } protected override void OnInit (EventArgs e) { CreateChildControls( ); base.OnInit(e); } protected override void OnLoad(EventArgs e) { base.EnsureChildControls( ); } protected void Page_Load(object sender, EventArgs e) { if (IsPostBack) { CreateChildControls( ); } } protected void lnkShowAllCust_Click(object sender, EventArgs e) { this.OnCustShowAllClicked(new EventArgs ( )); } protected virtual void OnCustShowAllClicked(EventArgs args) { if (this.ViewAllClicked != null) { this.ViewAllClicked(this, args); } } public event EventHandler ViewAllClicked; } I have been stuggling with this problem for the last 3 days and have had no success with it, and I really do need some help. Can anyone please help me?

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• Problem using a COM interface as parameter

  - by Cesar

  I have the following problem: I have to projects Project1 and Project2. In Project1 I have an interface IMyInterface. In Project2 I have an interface IMyInterface2 with a method that receives a pointer to IMyInterface1. When I use import "Project1.idl"; in my Project2.idl, a #include "Project1.h" appears in Project2___i.h. But this file does not even exist!. What is the proper way to import an interface defined into other library into a idl file? I tried to replace the #include "Project1.h" by *#include "Project1_i.h"* or *#include "Project1_i.c"*, but it gave me a lot of errors. I also tried to use importlib("Project1.tlb") and define my interface IMyInterface2 within the library definition. But when I compile Project2PS project, an error is raised (something like dlldata.c is not generated if no interface is defined). I tried to create a dummy Project1.h. But when Project2___i.h is compiled, compiler cannot find MyInterface1. And if I include Project1___i.h I get a lot of errors again! Apparently, it is a simple issue, but I don't know how to solve it. I'm stuck with that!. By the way, I'm using VS2008 SP1. Thanks in advance.

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• Visual C++ 2010, rvalue reference bug?

  - by Sergey Shandar

  Is it a bug in Visual C++ 2010 or right behaviour? template<class T> T f(T const &r) { return r; } template<class T> T f(T &&r) { static_assert(false, "no way"); return r; } int main() { int y = 4; f(y); } I thought, the function f(T &&) should never be called but it's called with T = int &. The output: main.cpp(10): error C2338: no way main.cpp(17) : see reference to function template instantiation 'T f<int&>(T)' being compiled with [ T=int & ] Update 1 Do you know any C++x0 compiler as a reference? I've tried comeau online test-drive but could not compile r-value reference. Update 2 Workaround (using SFINAE): #include <boost/utility/enable_if.hpp> #include <boost/type_traits/is_reference.hpp> template<class T> T f(T &r) { return r; } template<class T> typename ::boost::disable_if< ::boost::is_reference<T>, T>::type f(T &&r) { static_assert(false, "no way"); return r; } int main() { int y = 4; f(y); // f(5); // generates "no way" error, as expected. }

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• how can access public properties of MasterPage from external Class ?

  - by eugeneK

  Why i can't access MasterPage's public property (MessagePlaceholder) from other Class (Errors) ? Error compiler gives me is "Error 1 The type or namespace name 'MyMasterPage' could not be found (are you missing a using directive or an assembly reference?)" my master page code behind using System; using System.Collections.Generic; using System.Linq; using System.Web; using System.Web.UI; using System.Web.UI.WebControls; public partial class MyMasterPage : System.Web.UI.MasterPage { public string MessagePlaceholder { get { return messagePlaceholder.InnerHtml; } set { messagePlaceholder.InnerHtml = value; } } protected void Page_Load(object sender, EventArgs e) { if (!IsPostBack) { messagePlaceholder.InnerHtml = Errors.getMessage(); } } } my Errors Class public static string getMessage() { HttpContext c = HttpContext.Current; string messageType = ""; if (c.Session["errorMessage"] != null) { messageType = "errorMessage"; } else if (c.Session["successMessage"] != null) { messageType = "successMessage"; } if (!string.IsNullOrEmpty(messageType)) { StringBuilder userMessageSb = new StringBuilder(); userMessageSb.Append(string.Format("<div id=\"{0}\" title=\"{1}\">{2}</div>", messageType, messageType.Replace("Message",string.Empty), c.Session[messageType])); // fix so message will not re-appear c.Session.Remove(messageType); messageType = userMessageSb.ToString(); } return messageType; } public static void setSuccess(string successMessage, bool isRedirect) { HttpContext.Current.Session["successMessage"] = successMessage; } public static void setError(string errorMessage, bool isRedirect) { HttpContext.Current.Session["errorMessage"] = errorMessage; if (!isRedirect) { ((HttpContext.Current.CurrentHandler as System.Web.UI.Page).Master as MyMasterPage).MessagePlaceholder = getMessage(); } } this is how i set error if (true) { Errors.setError("this is an error demo", false); return; } or with redirect after error if (true) { Errors.setError("yet another error", true); Response.Redirect("~/error.aspx"); }

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• Why is it that an int in C++ that isnt initialized (then used) doesn't return an error?

  - by omizzle

  I am new to C++ (just starting). I come from a Java background and I was trying out the following piece of code that would sum the numbers between 1 and 10 (inclusive) and then print out the sum: /* * File: main.cpp * Author: omarestrella * * Created on June 7, 2010, 8:02 PM */ #include <cstdlib> #include <iostream> using namespace std; int main() { int sum; for(int x = 1; x <= 10; x++) { sum += x; } cout << "The sum is: " << sum << endl; return 0; } When I ran it it kept printing 32822 for the sum. I knew the answer was supposed to be 55 and realized that its print the max value for a short (32767) plus 55. Changing int sum; to int sum = 0; would work (as it should, since the variable needs to be initialized!). Why does this behavior happen, though? Why doesnt the compiler warn you about something like this? I know Java screams at you when something isnt initialized. Thank you.

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• How do C++ compilers actually pass reference parameters?

  - by T.E.D.

  This question came about as a result of some mixed-langauge programming. I had a Fortran routine I wanted to call from C++ code. Fortran passes all its parameters by reference (unless you tell it otherwise). So I thought I'd be clever (bad start right there) in my C++ code and define the Fortran routine something like this: extern "C" void FORTRAN_ROUTINE (unsigned & flag); This code worked for a while but (of course right when I needed to leave) suddenly started blowing up on a return call. Clear indication of a munged call stack. Another engineer came behind me and fixed the problem, declaring that the routine had to be deinfed in C++ as extern "C" void FORTRAN_ROUTINE (unsigned * flag); I'd accept that except for two things. One is that it seems rather counter-intuitive for the compiler to not pass reference parameters by reference, and I can find no documentation anywhere that says that. The other is that he changed a whole raft of other code in there at the same time, so it theoretically could have been another change that fixed whatever the issue was. So the question is, how does C++ actually pass reference parameters? Is it perhaps free to do copy-in, copy-out for small values or something? In other words, are reference parameters utterly useless in mixed-language programming? I'd like to know so I don't make this same code-killing mistake ever again.

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• Modifying bundled properties from visitor

  - by ravenspoint

  How should I modify the bundled properties of a vertex from inside a visitor? I would like to use the simple method of sub-scripting the graph, but the graph parameter passed into the visitor is const, so compiler disallows changes. I can store a reference to the graph in the visitor, but this seems weird. /** A visitor which identifies vertices as leafs or trees */ class bfs_vis_leaf_finder:public default_bfs_visitor { public: /** Constructor @param[in] total reference to int variable to store total number of leaves @param[in] g reference to graph ( used to modify bundled properties ) */ bfs_vis_leaf_finder( int& total, graph_t& g ) : myTotal( total ), myGraph( g ) { myTotal = 0; } /** Called when the search finds a new vertex If the vertex has no children, it is a leaf and the total leaf count is incremented */ template <typename Vertex, typename Graph> void discover_vertex( Vertex u, Graph& g) { if( out_edges( u, g ).first == out_edges( u, g ).second ) { myTotal++; //g[u].myLevel = s3d::cV::leaf; myGraph[u].myLevel = s3d::cV::leaf; } else { //g[u].myLevel = s3d::cV::tree; myGraph[u].myLevel = s3d::cV::tree; } } int& myTotal; graph_t& myGraph; };

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• Strange Access Denied warning when running the simplest C++ program.

  - by DaveJohnston

  I am just starting to learn C++ (coming from a Java background) and I have come across something that I can't explain. I am working through the C++ Primer book and doing the exercises. Every time I get to a new exercise I create a new .cpp file and set it up with the main method (and any includes I think I will need) e.g.: #include <list> #include <vector> int main(int argc, char **args) { } and just to make sure I go to the command prompt and compile and run: g++ whatever.cpp a.exe Normally this works just fine and I start working on the exercise, but I just did it and got a strange error. It compiles fine, but when I run it it says Access Denied and AVG pops up telling me that a threat has been detected 'Trojan Horse Generic 17.CKZT'. I tried compiling again using the Microsoft Compiler (cl.exe) and it runs fines. So I went back, and added: #include <iostream> compiled using g++ and ran. This time it worked fine. So can anyone tell me why AVG would report an empty main method as a trojan horse but if the iostream header is included it doesn't?

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• Asp.Net 2 integrated sites How to Logout second site programatically.

  - by NBrowne

  Hi , I am working with an asp.net 2.0 site (call it site 1) which has an iframe in it which loads up another site (site2) which is also an asp.net site which is developed by our team. When you log onto site 1 then behind the scenes site 2 is also logged in so that when you click the iframe tab then this displays site 2 with the user logged in (to prevent the user from having to log in twice). The problem i have is that when a user logs out of site 1 then we call some cleanup methods to perform FormsAuthentication.SignOut and clean session variables etc but at the moment no cleanup is called when the user on site 2. So the issue is that if the user opens up Site 2 from within a browser then website 2 opens with the user still logged in which is undesired. Can anyone give me some guidance as to the best approach for this?? One possible approach i though of was just that on click of logout button i could do a call to a custom page on Site 2 which would do the logout. Code below HttpWebRequest request; request = ((HttpWebRequest)(WebRequest.Create("www.mywebsite.com/Site2Logout.aspx"))); request.Method = "POST"; HttpCookie cookie = HttpContext.Current.Request.Cookies[FormsAuthentication.FormsCookieName]; Cookie authenticationCookie = new Cookie( FormsAuthentication.FormsCookieName, cookie.Value, cookie.Path, HttpContext.Current.Request.Url.Authority); request .CookieContainer = new CookieContainer(); request .CookieContainer.Add(authenticationCookie); response.GetResponse(); Problem i am having with this code is that when i run it and debug on Site 2 and check to see if the user is Authenticated they are not which i dont understand because if i open browser and browse to Site 2 i am Still authenticated. Any ideas , different direction to take etc ??? Please let me know if you need any more info or if i something i have said dosent make sense. Thanks

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• Segmentation fault on returning from main (very short and simple code, no arrays or pointers)

  - by Gábor Kovács

  I've been wondering why the following trivial code produces a segmentation fault when returning from main(): //Produces "Error while dumping state (probably corrupted stack); Segmentation fault" #include <iostream> #include <fstream> #include <vector> using namespace std; class Test { vector<int> numbers; }; int main() { Test a; ifstream infile; cout << "Last statement..." << endl; // this gets executed return 0; } Interestingly, 1) if only one of the two variables is declared, I don't get the error, 2) if I declare a vector variable instead of an object with a vector member, everything's fine, 3) if I declare an ofstream instead of an ifstream, again, everything works fine. Something appears to be wrong with this specific combination... Could this be a compiler bug? I use gcc version 3.4.4 with cygwin. Thanks for the tips in advance. Gábor

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• How to Prevent PostBack Event Handler from Firing

  - by user331744

  I have a custom class (ServerSideValidator.vb) that validates user input on server side (it doesn't use any of the .NET built in validators, therefore Page.Validate() is not an option for me). I am calling the Validate() method on page.IsPostback event and the class performs without any problem My issue is, when validation fails (returns false), I want to stop the postback event handler from firing, but load the page along with all the controls and user-input values in them. If I do, Response.End(), the page comes up blank. I can programmatically instruct the page to go to the previous page (original form before postback), but it loses all user-inputs. I thought of creating a global boolean variable in the page code behind file and check the value before performing any postback method, but this approach takes away from my plan to provide all functionalities inside the class itself. The page object is being referenced to ServerSideValidator. Seems like all the postback related properties/variables I come across inside Page class are 'Readonly' and I can't assign value(s) to control/prevent postback event from firing. Any idiea on how I can accomplish this? Please let me know if you need further details

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• Why do I get this strange output behavior?

  - by WilliamKF

  I have the following program test.cc: #include <iostream> unsigned char bogus1[] = { // Changing # of periods (0x2e) changes output after periods. 0x2e, 0x2e, 0x2e, 0x2e }; unsigned int bogus2 = 1816; // Changing this value changes output. int main() { std::clog << bogus1; } I build it with: g++ -g -c -o test.o test.cc; g++ -static-libgcc -o test test.o Using g++ version 3.4.6 I run it through valgrind and nothing is reported wrong. However the output has two extra control characters and looks like this: .... Thats a control-X and a control-G at the end. If you change the value of bogus2 you get different control characters. If you change the number of periods in the array the issue goes away or changes. I suspect it is a memory corruption bug in the compiler or iostream package. What is going on here?

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• Can knowing C actually hurt the code you write in higher level languages?

  - by Jurily

  The question seems settled, beaten to death even. Smart people have said smart things on the subject. To be a really good programmer, you need to know C. Or do you? I was enlightened twice this week. The first one made me realize that my assumptions don't go further than my knowledge behind them, and given the complexity of software running on my machine, that's almost non-existent. But what really drove it home was this Slashdot comment: The end result is that I notice the many naive ways in which traditional C "bare metal" programmers assume that higher level languages are implemented. They make bad "optimization" decisions in projects they influence, because they have no idea how a compiler works or how different a good runtime system may be from the naive macro-assembler model they understand. Then it hit me: C is just one more abstraction, like all others. Even the CPU itself is only an abstraction! I've just never seen it break, because I don't have the tools to measure it. I'm confused. Has my mind been mutilated beyond recovery, like Dijkstra said about BASIC? Am I living in a constant state of premature optimization? Is there hope for me, now that I realized I know nothing about anything? Is there anything to know, even? And why is it so fascinating, that everything I've written in the last five years might have been fundamentally wrong? To sum it up: is there any value in knowing more than the API docs tell me? EDIT: Made CW. Of course this also means now you must post examples of the interpreter/runtime optimizing better than we do :)

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• Can Haskell's monads be thought of as using and returning a hidden state parameter?

  - by AJM

  I don't understand the exact algebra and theory behind Haskell's monads. However, when I think about functional programming in general I get the impression that state would be modelled by taking an initial state and generating a copy of it to represent the next state. This is like when one list is appended to another; neither list gets modified, but a third list is created and returned. Is it therefore valid to think of monadic operations as implicitly taking an initial state object as a parameter and implicitly returning a final state object? These state objects would be hidden so that the programmer doesn't have to worry about them and to control how they gets accessed. So, the programmer would not try to copy the object representing the IO stream as it was ten minutes ago. In other words, if we have this code: main = do putStrLn "Enter your name:" name <- getLine putStrLn ( "Hello " ++ name ) ...is it OK to think of the IO monad and the "do" syntax as representing this style of code? putStrLn :: IOState -> String -> IOState getLine :: IOState -> (IOState, String) main :: IOState -> IOState -- main returns an IOState we can call "state3" main state0 = putStrLn state2 ("Hello " ++ name) where (state2, name) = getLine state1 state1 = putStrLn state0 "Enter your name:"

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• What are the general strategies for the server of an FPS multiplayer game to update its clients?

  - by Hooray Im Helping

  A friend and I were having a discussion about how a FPS server updates the clients connected to it. We watched a video of a guy cheating in Battlefield: Bad Company 2 and saw how it highlighted the position of enemies on the screen and it got us thinking. His contention was that the server only updates the client with information that is immediately relevant to the client. I.e. the server won't send information about enemy players if they are too far away from the client or out of the client's line of sight for reasons of efficiency. He was unsure though - he brought up the example of someone hiding behind a rock, not able to see anyone. If the player were suddenly to pop up where he had three players in his line of sight, there would be a 50ms delay before they were rendered on his screen while the server transmitted the necessary information. My contention was the opposite: that the server sends the client all the information about every player and lets the client sort out what is allowed and what isn't. I figured it would actually be less expensive computationally for the server to just send everything to the client and let the client do the heavy lifting, so to speak. I also figured this is how cheat programs work - they intercept the server packets, get the location of enemies, then show them on the client's view. So the question: What are some general policies or strategies a modern first person shooter server employs to keep its clients updated?

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• Using resources with the same name in Xcode

  - by Roberto

  Is there a way to add multiple resources with the same name to an Xcode project and have 1 of them take priority over the others? Example: I added 2 files, both called icon.png, to an Xcode project. They are on different folders in the file system (Folder1/icon.png and Folder2/icon.png) and on different groups in Xcode. Is there a way to tell Xcode to have Folder2/icon.png take priority over Folder1/icon.png? And if only 1 icon.png exists, then use that one. Thanks. EDIT (2010-12-23): You can have multiple files with the same name in an Xcode project even if they are not in separate folder references, but they are in separate groups. Once compiled, the app bundle (which will be flat with no folders in it), will only have one copy of the file (icon.png). How do you pick which copy of the file to use? I was told that you can do this for BlackBerry. It works something like this: The compiler will go down the list of files in the project and start adding them to the app bundle. If it sees a duplicate, it will overwrite it (or not), so the files at the bottom (or at the top) will have higher precedence and will be the final bundle.

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• Segmentation Fault when trying to push a string to the back of a list.

  - by user308012

  I am trying to write a logger class for my C++ calculator, but I'm experiencing a problem while trying to push a string into a list. I have tried researching this issue and have found some information on this, but nothing that seems to help with my problem. I am using a rather basic C++ compiler, with little debugging utilities and I've not used C++ in quite some time (even then it was only a small amount). My code: #ifndef _LOGGER_H_ #define _LOGGER_H_ #include <iostream> #include <list> #include <string> using std::cout; using std::cin; using std::endl; using std::list; using std::string; class Logger { private: list<string> *mEntries; public: Logger() { // Initialize the entries list mEntries = new list<string>(); } ~Logger() { // Release the list mEntries->clear(); delete mEntries; } // Public Methods void WriteEntry(string entry) { // *** BELOW LINE IS MARKED WITH THE ERROR *** mEntries->push_back(string(entryData)); } void DisplayEntries() { cout << endl << "**********************" << endl << "* Logger Entries *" << endl << "**********************" << endl << endl; for(list<string>::iterator it = mEntries->begin(); it != mEntries->end(); it++) { cout << *it << endl; } } }; #endif I am calling the WriteEntry method by simply passing in a string, like so: mLogger->WriteEntry("Testing"); Any advice on this would be greatly appreciated.

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• How to configure Server Topology for exposing an internal application for external access?

  - by ronaldwidha

  Hi All, I guess this question is bordering to a Server Fault question. I'd like to know the best configuration for exposing an internal application (in this case a load balanced Asp.Net MVC application) for external access. More details about the situation: The Asp.Net MVC Application is currently running on 2 servers The 2 servers are behind a Windows Network Load Balancer All the servers are on premise/internal network I'm thinking of introducing an F5 Load balancer on off premise DMZ to replace the Windows Network Load Balancer. F5 will act as the public traffic gateway and load balancers to the 2 servers. However, I'd like the internal users to not have go through the Internet to access the app. The idea that I have so far is to keep both Windows Network Load Balancer and the F5. Each appliance will have its own IP and will have its own domain name. External users can use the public domain name which will hit F5, whereas internal users can use the internal domain name which will hit the Windows Network Load Balancer. Is this a good idea? Or is there a better way of doing this?

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• Connection Pool Strategy: Good, Bad or Ugly?

  - by Drew

  I'm in charge of developing and maintaining a group of Web Applications that are centered around similar data. The architecture I decided on at the time was that each application would have their own database and web-root application. Each application maintains a connection pool to its own database and a central database for shared data (logins, etc.) A co-worker has been positing that this strategy will not scale because having so many different connection pools will not be scalable and that we should refactor the database so that all of the different applications use a single central database and that any modifications that may be unique to a system will need to be reflected from that one database and then use a single pool powered by Tomcat. He has posited that there is a lot of "meta data" that goes back and forth across the network to maintain a connection pool. My understanding is that with proper tuning to use only as many connections as necessary across the different pools (low volume apps getting less connections, high volume apps getting more, etc.) that the number of pools doesn't matter compared to the number of connections or more formally that the difference in overhead required to maintain 3 pools of 10 connections is negligible compared to 1 pool of 30 connections. The reasoning behind initially breaking the systems into a one-app-one-database design was that there are likely going to be differences between the apps and that each system could make modifications on the schema as needed. Similarly, it eliminated the possibility of system data bleeding through to other apps. Unfortunately there is not strong leadership in the company to make a hard decision. Although my co-worker is backing up his worries only with vagueness, I want to make sure I understand the ramifications of multiple small databases/connections versus one large database/connection pool.

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• C++ : integer constant is too large for its type

  - by user38586

  I need to bruteforce a year for an exercise. The compiler keep throwing this error: bruteforceJS12.cpp:8:28: warning: integer constant is too large for its type [enabled by default] My code is: #include <iostream> using namespace std; int main(){ unsigned long long year(0); unsigned long long result(318338237039211050000); unsigned long long pass(1337); while (pass != result) { for (unsigned long long i = 1; i<= year; i++) { pass += year * i * year; } cout << "pass not cracked with year = " << year << endl; ++year; } cout << "pass cracked with year = " << year << endl; } Note that I already tried with unsigned long long result(318338237039211050000ULL); I'm using gcc version 4.8.1 EDIT: Here is the corrected version using InfInt library http://code.google.com/p/infint/ #include <iostream> #include "InfInt.h" using namespace std; int main(){ InfInt year = "113"; InfInt result = "318338237039211050000"; InfInt pass= "1337"; while (pass != result) { for (InfInt i = 1; i<= year; i++) { pass += year * i * year; } cout << "year = " << year << " pass = " << pass << endl; ++year; } cout << "pass cracked with year = " << year << endl; }

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• Why do I have to specify pure virtual functions in the declaration of a derived class in Visual C++?

  - by neuviemeporte

  Given the base class A and the derived class B: class A { public: virtual void f() = 0; }; class B : public A { public: void g(); }; void B::g() { cout << "Yay!"; } void B::f() { cout << "Argh!"; } I get errors saying that f() is not declared in B while trying do define void B::f(). Do I have to declare f() explicitly in B? I think that if the interface changes I shouldn't have to correct the declarations in every single class deriving from it. Is there no way for B to get all the virtual functions' declarations from A automatically? EDIT: I found an article that says the inheritance of pure virtual functions is dependent on the compiler: http://www.objectmentor.com/resources/articles/abcpvf.pdf I'm using VC++2008, wonder if there's an option for this.

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• How do I add the go language to gitg's list of viewable sources?

  - by Hotei

  Hoping a 'git' guru will help out here. I am just beginning to "git" for the first time and have (among other things :-) ) git and gitg installed from Ubuntu 10.4 / AMD64 distribution (ie. maybe not 'latest' version but not ancient). I am trying to look at the go code I've committed via gitg and in the "tree tab" it says :Cannot display file content as text. However, the "details tab" shows the diffs of the same file just fine. I know gitg's "tree tab" is working because I can use the tree view on *.c / *.html / *.txt etc just fine. Is there a way to tweak gitg into understanding that "*.go" is just text? A little more context: Installed gitg version is 0.0.5 - ie a version behind latest - 0.0.6 - source of which I am looking thru now. I do have a working /usr/share/gtksourceview-2.0/language-specs/ go.lang. It works just fine as highlighter in gedit. It appears that gitg may require displayable files to have a mime type of "text/plain", so I added that to go.lang No joy. gitg still fails on *.go I'm relatively sure the fix is simple, just don't know where to look.

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