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  • compiler warning at C++ template base class

    - by eike
    I get a compiler warning, that I don't understand in that context, when I compile the "Child.cpp" from the following code. (Don't wonder: I stripped off my class declarations to the bare minuum, so the content will not make much sense, but you will see the problem quicker). I get the warning with VS2003 and VS2008 on the highest warning level. The code AbstractClass.h : #include <iostream> template<typename T> class AbstractClass { public: virtual void Cancel(); // { std::cout << "Abstract Cancel" << std::endl; }; virtual void Process() = 0; }; //outside definition. if I comment out this and take the inline //definition like above (currently commented out), I don't get //a compiler warning template<typename T> void AbstractClass<T>::Cancel() { std::cout << "Abstract Cancel" << std::endl; } Child.h : #include "AbstractClass.h" class Child : public AbstractClass<int> { public: virtual void Process(); }; Child.cpp : #include "Child.h" #include <iostream> void Child::Process() { std::cout << "Process" << std::endl; } The warning The class "Child" is derived from "AbstractClass". In "AbstractClass" there's the public method "AbstractClass::Cancel()". If I define the method outside of the class body (like in the code you see), I get the compiler warning... AbstractClass.h(7) : warning C4505: 'AbstractClass::Cancel' : unreferenced local function has been removed with [T=int] ...when I compile "Child.cpp". I do not understand this, because this is a public function and the compiler can't know if I later reference this method or not. And, in the end, I reference this method, because I call it in main.cpp and despite this compiler warning, this method works if I compile and link all files and execute the program: //main.cpp #include <iostream> #include "Child.h" int main() { Child child; child.Cancel(); //works, despite the warning } If I do define the Cancel() function as inline (you see it as out commented code in AbstractClass.h), then I don't get the compiler warning. Of course my program works, but I want to understand this warning or is this just a compiler mistake? Furthermore, if do not implement AbsctractClass as a template class (just for a test purpose in this case) I also don't get the compiler warning...?

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  • Boost singleton and restricted

    - by Ockonal
    Hello, I'm using boost singleton from thread/detail. There is in manual, that constructor should have signlature: boost::restricted. But I can't find any reference for this type in boost library. Why do I need in this and where I can find it?

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  • Perl, array referencing

    - by Mike
    Consider this Perl code my @a=[[1]]; print $a[0][0] . "\n"; **output** ARRAY(0x229e8) Why does it print an Array instead of 1? I would have expected @a to create an array of size 1 with a reference to a second array containing only one element, 1

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  • Unique element ID, even if element doesn't have one

    - by Robert J. Walker
    I'm writing a GreaseMonkey script where I'm iterating through a bunch of elements. For each element, I need a string ID that I can use to reference that element later. The element itself doesn't have an id attribute, and I can't modify the original document to give it one (although I can make DOM changes in my script). I can't store the references in my script because when I need them, the GreaseMonkey script itself will have gone out of scope. Is there some way to get at an "internal" ID that the browser uses, for example? A Firefox-only solution is fine; a cross-browser solution that could be applied in other scenarios would be awesome. Edit: If the GreaseMonkey script is out of scope, how are you referencing the elements later? They GreaseMonkey script is adding events to DOM objects. I can't store the references in an array or some other similar mechanism because when the event fires, the array will be gone because the GreaseMonkey script will have gone out of scope. So the event needs some way to know about the element reference that the script had when the event was attached. And the element in question is not the one to which it is attached. Can't you just use a custom property on the element? Yes, but the problem is on the lookup. I'd have to resort to iterating through all the elements looking for the one that has that custom property set to the desired id. That would work, sure, but in large documents it could be very time consuming. I'm looking for something where the browser can do the lookup grunt work. Wait, can you or can you not modify the document? I can't modify the source document, but I can make DOM changes in the script. I'll clarify in the question. Can you not use closures? Closuses did turn out to work, although I initially thought they wouldn't. See my later post. It sounds like the answer to the question: "Is there some internal browser ID I could use?" is "No."

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  • Flash AS 3.0 building a message console approach

    - by vasion
    I am having trouble figuring out how to build a console for my application so i can send msgs to it from any class in the package. i tried to send a generic Event, but I cannot find a way send a msg together with the event, or at least a reference to the object which is dispatching the event. what approach would you suggest?

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  • NHibernate (3.1.0.4000) NullReferenceException using Query<> and NHibernate Facility

    - by TigerShark
    I have a problem with NHibernate, I can't seem to find any solution for. In my project I have a simple entity (Batch), but whenever I try and run the following test, I get an exception. I've triede a couple of different ways to perform a similar query, but almost identical exception for all (it differs in which LINQ method being executed). The first test: [Test] public void QueryLatestBatch() { using (var session = SessionManager.OpenSession()) { var batch = session.Query<Batch>() .FirstOrDefault(); Assert.That(batch, Is.Not.Null); } } The exception: System.NullReferenceException : Object reference not set to an instance of an object. at NHibernate.Linq.NhQueryProvider.PrepareQuery(Expression expression, ref IQuery query, ref NhLinqExpression nhQuery) at NHibernate.Linq.NhQueryProvider.Execute(Expression expression) at System.Linq.Queryable.FirstOrDefault(IQueryable`1 source) The second test: [Test] public void QueryLatestBatch2() { using (var session = SessionManager.OpenSession()) { var batch = session.Query<Batch>() .OrderBy(x => x.Executed) .Take(1) .SingleOrDefault(); Assert.That(batch, Is.Not.Null); } } The exception: System.NullReferenceException : Object reference not set to an instance of an object. at NHibernate.Linq.NhQueryProvider.PrepareQuery(Expression expression, ref IQuery query, ref NhLinqExpression nhQuery) at NHibernate.Linq.NhQueryProvider.Execute(Expression expression) at System.Linq.Queryable.SingleOrDefault(IQueryable`1 source) However, this one is passing (using QueryOver<): [Test] public void QueryOverLatestBatch() { using (var session = SessionManager.OpenSession()) { var batch = session.QueryOver<Batch>() .OrderBy(x => x.Executed).Asc .Take(1) .SingleOrDefault(); Assert.That(batch, Is.Not.Null); Assert.That(batch.Executed, Is.LessThan(DateTime.Now)); } } Using the QueryOver< API is not bad at all, but I'm just kind of baffled that the Query< API isn't working, which is kind of sad, since the First() operation is very concise, and our developers really enjoy LINQ. I really hope there is a solution to this, as it seems strange if these methods are failing such a simple test. EDIT I'm using Oracle 11g, my mappings are done with FluentNHibernate registered through Castle Windsor with the NHibernate Facility. As I wrote, the odd thing is that the query works perfectly with the QueryOver< API, but not through LINQ.

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  • How is hashCode() calculated in Java.

    - by Jothi
    What value is hashCode() method is returning in java?. i read that it is an memory reference of an object. when i print hascode value for new Integer(1), its 1. for String(a) - 97. so i confused. is it ascii or what type of value is?

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  • Error: Class 'Haml' not found... trying to use Haml (Kohaml) with Kohana

    - by Serhiy
    Can't for the life of me figure out what I'm doing wrong... Downloaded Kohaml from http://github.com/transphorm/kohaml Dropped it into modules/kohaml # My Bootstrap reference 'kohaml' => MODPATH.'kohaml', // kohaml Keep getting this error... (snapshot of the error and my modules folder) http://wellcommentedcode.com/stack_kohaml_question/ Any suggestions on what I might be doing wrong would be highly appreciated... thanks.

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  • What is the "box model?"

    - by Chris
    During a recent interview for a front-end developer position I was asked what the box model was. I thought the interviewer was referring to testing (i.e. white box testing, black box testing). I was wrong. What is the box model, in reference to front-end development?

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  • SQL Query to truncate table in IBM DB2

    - by Cshah
    Hi, Can any one give me the syntax to truncate a table in IBM DB2. I m running the following command: truncate table tableName immediate; The eror is DB2 SQL Error: SQLCODE=-104, SQLSTATE=42601, SQLERRMC=table;truncate ;JOIN , DRIVER=3.50.152 Message: An unexpected token "table" was found following "truncate ". Expected tokens may include: "JOIN ".. SQLCODE=-104, SQLSTATE=42601, DRIVER=3.50.152 The syntax matches the one specified in the reference docs of IBM : http://publib.boulder.ibm.com/infocenter/dzichelp/v2r2/index.jsp?topic=/com.ibm.db29.doc.sqlref/db2z_sql_truncate.htm

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  • When is it appropriate to use error codes?

    - by Jim Hurne
    In languages that support exception objects (Java, C#), when is it appropriate to use error codes? Is the use of error codes ever appropriate in typical enterprise applications? Many well-known software systems employ error codes (and a corresponding error code reference). Some examples include operating systems (Windows), databases (Oracle, DB2), and middle-ware products (WebLogic, WebSphere). What benefits do error codes provide? What are the disadvantages to using error codes?

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  • Accessing Sabre Web Services using PHP

    - by Peter
    I have been approached to create a website using Sabre Web Services to power the reservations system. All documentation I have seen refers to .NET or Java solutions, I was in doubt whether PHP can be used as access is performed using SOAP. I have found no further information about this, I assume the answer is yes, but wonder why there is not a single reference to this being possible - all solutions seem to be .NET Any suggestions? Thanks!

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  • Java String.replaceAll regex

    - by atomsfat
    I want to replace the first context of web/style/clients.html with the java String.replaceFirst method so I can get: ${pageContext.request.contextPath}/style/clients.html I tried String test = "web/style/clients.html".replaceFirst("^.*?/", "hello/"); And this give me: hello/style/clients.html but when I do String test = "web/style/clients.html".replaceFirst("^.*?/", "${pageContext.request.contextPath}/"); gives me java.lang.IllegalArgumentException: Illegal group reference

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  • wrong operator() overload called

    - by user313202
    okay, I am writing a matrix class and have overloaded the function call operator twice. The core of the matrix is a 2D double array. I am using the MinGW GCC compiler called from a windows console. the first overload is meant to return a double from the array (for viewing an element). the second overload is meant to return a reference to a location in the array (for changing the data in that location. double operator()(int row, int col) const ; //allows view of element double &operator()(int row, int col); //allows assignment of element I am writing a testing routine and have discovered that the "viewing" overload never gets called. for some reason the compiler "defaults" to calling the overload that returns a reference when the following printf() statement is used. fprintf(outp, "%6.2f\t", testMatD(i,j)); I understand that I'm insulting the gods by writing my own matrix class without using vectors and testing with C I/O functions. I will be punished thoroughly in the afterlife, no need to do it here. Ultimately I'd like to know what is going on here and how to fix it. I'd prefer to use the cleaner looking operator overloads rather than member functions. Any ideas? -Cal the matrix class: irrelevant code omitted class Matrix { public: double getElement(int row, int col)const; //returns the element at row,col //operator overloads double operator()(int row, int col) const ; //allows view of element double &operator()(int row, int col); //allows assignment of element private: //data members double **array; //pointer to data array }; double Matrix::getElement(int row, int col)const{ //transform indices into true coordinates (from sorted coordinates //only row needs to be transformed (user can only sort by row) row = sortedArray[row]; result = array[usrZeroRow+row][usrZeroCol+col]; return result; } //operator overloads double Matrix::operator()(int row, int col) const { //this overload is used when viewing an element return getElement(row,col); } double &Matrix::operator()(int row, int col){ //this overload is used when placing an element return array[row+usrZeroRow][col+usrZeroCol]; } The testing program: irrelevant code omitted int main(void){ FILE *outp; outp = fopen("test_output.txt", "w+"); Matrix testMatD(5,7); //construct 5x7 matrix //some initializations omitted fprintf(outp, "%6.2f\t", testMatD(i,j)); //calls the wrong overload }

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  • MongoDB and visual C++ 2008 linker errors

    - by pedlar
    i'm trying to get the c++ client for mongodb working in visual studio 2008. i can reference the includes, but whenever i tell the linker about the mongodb .lib file i get the following error: "fatal error LNK1257: code generation failed". if visual studio can't find the .lib, then i get a bunch of unresolved externals errors. i'm really pretty lost at this point.

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  • Accessing the ASP.NET Cache from a Separate Thread?

    - by maxp
    Normally i have a static class that reads and writes to HttpContext.Current.Cache However since adding threading to my project, the threads all get null reference exceptions when trying to retrieve this object. Is there any other way i can access it, workarounds or another cache i can use?

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  • storing HTML5 webdatabase table data to sql server periodically

    - by DotnetSparrow
    I want to read data from html5 web database and post to sql server using vb.net server side. I have used following link as reference: http://www.html5rocks.com/en/tutorials/webdatabase/todo/ I have created a web database and created table and stored some data in it. Now I want to store this data to sql server. How to get the data from html 5 web database and post to sql server each hour ( using some js timer). Please suggest solution

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  • Load WPF styles (static resources) from an external assembly

    - by Shimmy
    I have a few WPF applications and I want all my styles to be in a shared assembly instead of declaring them in each application separately. I am looking for a way so I don't have to change all my Style="{StaticResource BlahBlah}" in the existing applications; I just want to add the reference to this style assembly, and delete it from the current application, so it's taken from the assembly. Is there any way?

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  • Best way to copy the entire contents of a directory in C#

    - by Keith
    I want to copy the entire contents of a directory from one location to another in C#. There doesn't appear to be a way to do this using System.IO classes without lots of recursion. There is a method in VB that we can use if we add a reference to Microsoft.VisualBasic: new Microsoft.VisualBasic.Devices.Computer(). FileSystem.CopyDirectory( sourceFolder, outputFolder ); This seems like a rather ugly hack. Is there a better way?

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