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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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  • COCOA: Programatically creating new windows and accessing window objects

    - by Jeffrey Kern
    I'm having an issue with creating new windows in Cocoa. Hypothetically speaking, lets say I have "WindowA" and has a button called "myButton". When you click on "myButton", it runs this code in the following class file: -(void)openFile2:(id)sender { myNextWindow = [[TestWindowController alloc] initWithWindowNibName:@"MainMenu"]; NSString *testString = @"foo"; [myNextWindow showWindow:self]; [myNextWindow setButtonText:testString]; } The code in a nutshell makes a duplicate "WindowA" and shows it. As you can see, this code also runs a method called 'setButtonText', which is this: - (void)setButtonText:(NSString *)passedText { [myButton setTitle:passedText]; } The problem is that when I call this method locally, in the original window - the button text changes (e.g., [self setButtonText:testString]) it works. However, it does not work in the newly created window (e.g., [myNextWindow setButtonText:testString];) When I debug the newly created window, step by step, the 'myButton' value it gives is 0x0. Do I have to manually assign controllers/delegates to the new window? I think the 'myButton' in the code isn't associated to the 'myButton' in the newly created window. How would I fix this problem?

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  • How to write syntax highlighting? c++

    - by ML
    Hi All, I am embarking on some learning and I want to write my own syntax highlighting for files in C++. Can anyone give me ideas on how to go about doing this? To me it seems that when a file is opened: 1. it would need to be parsed and decided what type of source file it is. Trusting the extension might not be full-proof a way to know what keywords/commands apply to what language a way to decide what color each keyword/command gets I want to do this on OS X, C++ or Objective-C Can anyone provide pointers on how I might get started with this?

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  • Is it a bug???????????????/

    - by Knowing me knowing you
    I'm using VS2010 Ultimate. Having code: //file IntSet.h #include "stdafx.h" #pragma once /*Class representing set of integers*/ template<class T> class IntSet { private: T** myData_; std::size_t mySize_; std::size_t myIndex_; public: #pragma region ctor/dtor explicit IntSet(); virtual ~IntSet(); #pragma endregion #pragma region publicInterface IntSet makeUnion(const IntSet&)const; IntSet makeIntersection(const IntSet&)const; IntSet makeSymmetricDifference(const IntSet&)const; void insert(const T&); #pragma endregion }; //file IntSet_impl.h #include "StdAfx.h" #include "IntSet.h" #pragma region ctor/dtor template<class T> IntSet<T>::IntSet():myData_(nullptr), mySize_(0), myIndex_(0) { } template<class T> IntSet<T>::~IntSet() { } #pragma endregion #pragma region publicInterface template<class T> void IntSet<T>::insert(const T& obj) {/*IF I SET A BREAKPOINT HERE AND AFTER THAT I CHANGE SOMETHING IN THE BODY I'M GETTING MSG SAYING THAT THE BREAKPOINT WILL NOT CURRENTLY BE HIT, AFTER I REBUILD THE BREAKPOINT IS VALID AGAIN*/ /*Check if we are initialized*/ if (mySize_ == 0) { mySize_ = 1; myData_ = new T*[mySize_]; } /*Check if we have place to insert obj in.*/ if (myIndex_ < mySize_) { myData_[myIndex_++] = new T(obj); return; } /*We didn't have enough place...*/ T** tmp = new T*[mySize_];//for copying old to temporary basket std::copy(&myData_[0],&myData_[mySize_],&tmp[0]); delete myData_; auto oldSize = mySize_; mySize_ *= 2; myData_ = new T*[mySize_]; std::copy(&tmp[0],&tmp[oldSize],&myData_[0]); myData_[myIndex_] = new T(obj); ++myIndex_; } #pragma endregion Thanks.

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  • VB.NET custom user control graphics rotation

    - by AtharvaI
    Hi, this is my first question on here. I'm trying to build a dial control as a custom user control in VB.NET. I'm using VS2008. so far I have managed to rotate image using graphics.rotatetransform . however, this rotate everything. Now I have a Bitmap for the dial which should stay stable and another Bitmap for the needle which I need to rotate. so far i've tried this: Dim gL As Graphics = Graphics.FromImage(bmpLongNeedle) gL.TranslateTransform(bmpLongNeedle.Width / 2, bmpLongNeedle.Height * 0.74) gL.RotateTransform(angleLongNeedle) gL.TranslateTransform(-bmpLongNeedle.Width / 2, -bmpLongNeedle.Height * 0.74) gL.DrawImage(bmpLongNeedle, 0, 0) As I understand it, the image of the needle should be rotated at angle "angleLongNeedle" although i'm placing the rotated image at 0,0. However, the result is that the Needle doesn't get drawn on the control. any pointers as to where I might be going wrong or something else I should be doing? Thanks in advance

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  • C -- Basic Struct questions

    - by Ryan Yu
    So I'm trying to learn C right now, and I have some basic struct questions I'd like to clear up: Basically, everything centers around this snippet of code: #include <stdio.h> #include <stdlib.h> #define MAX_NAME_LEN 127 typedef struct { char name[MAX_NAME_LEN + 1]; unsigned long sid; } Student; /* return the name of student s */ const char* getName (const Student* s) { // the parameter 's' is a pointer to a Student struct return s->name; // returns the 'name' member of a Student struct } /* set the name of student s If name is too long, cut off characters after the maximum number of characters allowed. */ void setName(Student* s, const char* name) { // 's' is a pointer to a Student struct | 'name' is a pointer to the first element of a char array (repres. a string) s->name = name; } /* return the SID of student s */ unsigned long getStudentID(const Student* s) { // 's' is a pointer to a Student struct return s->sid; } /* set the SID of student s */ void setStudentID(Student* s, unsigned long sid) { // 's' is a pointer to a Student struct | 'sid' is a 'long' representing the desired SID s->sid = sid; } I've commented up the code in an attempt to solidify my understanding of pointers; I hope they're all accurate. So anyway, I have a feeling that setName and setStudentID aren't correct, but I'm not exactly sure why. Can someone explain? Thanks!

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  • java array pass by reference does not work?

    - by stdnoit
    guys i thought almost all language including java pass array into function as reference (modifiable) but somehow it does not work here. and the testArray is still 1,2,3 with size of 3 strange enough, when if i change result[i] = 2 to a[1] =2; it work . it did pass by reference what is wrong with this code? at the end, i had a = result; (which update the a). did result get removed from stack. that is why a still get to the original a ? i am confused. thanks class Test { public static void main(String[] args) { int[] testArray = {1,2,3}; equalize(testArray, 6); System.out.println("test Array size :" + testArray.length); for(int i = 0; i < testArray.length; i++) System.out.println(testArray[i]); } public static void equalize(int[] a, int biggerSize) { if(a.length > biggerSize) throw new Error("Array size bigger than biggerSize"); int[] result = new int[biggerSize]; // System.arraycopy(a, 0, result, 0, a.length); // int array default value should be 0 for(int i = 0; i < biggerSize; i++) result[i] = 2; a = result; } }

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  • How do I output an individual character when using char *[] = "something"

    - by Matt
    I've been playing with pointers to better understand them and I came across something I think I should be able to do, but can't sort out how. The code below works fine - I can output "a", "dog", "socks", and "pants" - but what if I wanted to just output the 'o' from "socks"? How would I do that? char *mars[4] = { "a", "dog", "sock", "pants" }; for ( int counter = 0; counter < 4; counter++ ) { cout << mars[ counter ]; } Please forgive me if the question is answered somewhere - there are 30+ pages of C++ pointer related question, and I spent about 90 minutes looking through them, as well as reading various (very informative) articles, before deciding to ask.

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  • JPA returning null for deleted items from a set

    - by Jon
    This may be related to my question from a few days ago, but I'm not even sure how to explain this part. (It's an entirely different parent-child relationship.) In my interface, I have a set of attributes (Attribute) and valid values (ValidValue) for each one in a one-to-many relationship. In the Spring MVC frontend, I have a page for an administrator to edit these values. Once it's submitted, if any of these fields (as <input> tags) are blank, I remove the ValidValue object like so: Set<ValidValue> existingValues = new HashSet<ValidValue>(attribute.getValidValues()); Set<ValidValue> finalValues = new HashSet<ValidValue>(); for(ValidValue validValue : attribute.getValidValues()) { if(!validValue.getValue().isEmpty()) { finalValues.add(validValue); } } existingValues.removeAll(finalValues); for(ValidValue removedValue : existingValues) { getApplicationDataService().removeValidValue(removedValue); } attribute.setValidValues(finalValues); getApplicationDataService().modifyAttribute(attribute); The problem is that while the database is updated appropriately, the next time I query for the Attribute objects, they're returned with an extra entry in their ValidValue set -- a null, and thus, the next time I iterate through the values to display, it shows an extra blank value in the middle. I've confirmed that this happens at the point of a merge or find, at the point of "Execute query ReadObjectQuery(entity.Attribute). Here's the code I'm using to modify the database (in the ApplicationDataService): public void modifyAttribute(Attribute attribute) { getJpaTemplate().merge(attribute); } public void removeValidValue(ValidValue removedValue) { ValidValue merged = getJpaTemplate().merge(removedValue); getJpaTemplate().remove(merged); } Here are the relevant parts of the entity classes: Entity @Table(name = "attribute") public class Attribute { @OneToMany(cascade = CascadeType.ALL, fetch = FetchType.LAZY, mappedBy = "attribute") private Set<ValidValue> validValues = new HashSet<ValidValue>(0); } @Entity @Table(name = "valid_value") public class ValidValue { @ManyToOne(fetch = FetchType.LAZY) @JoinColumn(name = "attr_id", nullable = false) private Attribute attribute; }

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  • Are TestContext.Properties usable ?

    - by DBJDBJ
    Using Visual Studio generate Test Unit class. Then comment in, the class initialization method. Inside it add your property, using the testContext argument. Upon test app startup this method is indeed called by the testing infrastructure. //Use ClassInitialize to run code before running the first test in the class [ClassInitialize()] public static void MyClassInitialize(TestContext testContext) { /* * Any user defined testContext.Properties * added here will be erased after this method exits */ testContext.Properties.Add("key", 1 ) ; // place the break point here } After leaving MyClassInitialize, any properties added by user are lost. Only the 10 "official" ones are left. Actually TestContext gets overwritten, with the inital offical one, each time before each test method is called. It it not overwritten only if user has test initialization method, the changes made over there are passed to the test. //Use TestInitialize to run code before running each test [TestInitialize()]public void MyTestInitialize(){ this.TestContext.Properties.Add("this is preserved",1) ; } This effectively means TestContext.Properties is "mostly" read only, for users. Which is not clearly documented in MSDN. It seems to me this is very messy design+implementation. Why having TestContext.Properties as an collection, at all ? Users can do many other solutions to have class wide initialization. Please discuss. --DBJ

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  • Help with c# event listening and usercontrols

    - by Jen
    OK so I have a page which has a listview on it. Inside the item template of the listview is a usercontrol. This usercontrol is trying to trigger an event so that the hosting page can listen to it. My problem is that the event is not being triggered as the handler is null. (ie. EditDateRateSelected is my handler and its null when debugging) protected void lnkEditDate_Click(object sender, EventArgs e) { if (EditDateRateSelected != null) EditDateRateSelected(Convert.ToDateTime(((LinkButton)frmViewRatesDate.Row.FindControl("lnkEditDate")).Text)); } On the item data bound of my listvew is where I'm adding my event handlers protected void PropertyAccommodationRates1_ItemDataBound(object sender, ListViewItemEventArgs e) { if (e.Item.ItemType == ListViewItemType.DataItem) { UserControls_RatesEditDate RatesViewDate1 = (UserControls_RatesEditDate)e.Item.FindControl("RatesViewDate1"); RatesViewDate1.EditDateRateSelected += new UserControls_RatesEditDate.EditDateRateEventHandler(RatesEditDate1_EditDateRateSelected); RatesViewDate1.PropertyID = (int)Master.PropertyId; if (!String.IsNullOrEmpty(Accommodations1.SelectedValue)) { RatesViewDate1.AccommodationTypeID = Convert.ToInt32(Accommodations1.SelectedValue); } else { RatesViewDate1.AccommodationTypeID = 0; } RatesViewDate1.Rate = (PropertyCMSRate)((ListViewDataItem)e.Item).DataItem; } } My event code all works fine if the control is inside the page and on page load I have the line: RatesEditDate1.EditDateRateSelected += new UserControls_RatesEditDate.EditDateRateEventHandler(RatesEditDate1_EditDateRateSelected); But obviously I need listen for events inside the listviewcontrols. Any advice would be greatly appreciated. I have tried setting EnableViewState to true for my listview but that hasn't made a difference. Is there somewhere else I'm supposed to be wiring up the control handler? Note - apologies if I've got my terminology wrong and I'm referring to delegates as handlers and such :)

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  • N3WB Question: passing objects in java?

    - by Adam Outler
    Hello, I am new at java. I am doing the following: Read from file, then put data into a variable. checkToken = lineToken.nextToken(); processlinetoken() } But then when I try to process it... public static void readFile(String fromFile) throws IOException { BufferedReader reader = new BufferedReader(new FileReader(fromFile)); String line = null; while ((line=reader.readLine()) != null ) { if (line.length() >= 2) { StringTokenizer lineToken = new StringTokenizer (line); checkToken = lineToken.nextToken(); ...... But here's where I come into a problem. public static void processlinetoken() checkToken=lineToken.nextToken(); } it fails out. Exception in thread "main" java.lang.Error: Unresolved compilation problem: The method nextToken() is undefined for the type String at testread.getEngineLoad(testread.java:243) at testread.readFile(testread.java:149) at testread.main(testread.java:119) so how do I get this to work? It seems to pass the variable, but nothing after the . works.

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  • Creating a C++ DLL and then using it in C#

    - by Major
    Ok I'm trying to make a C++ DLL that I can then call and reference in a c# App. I've already made a simple dll using the numberous guides out there, however when I try to reference it in the C# app I get the error Unable to load DLL 'SDES.dll': The specified module could not be found. The code for the program is as follows (bear with me I'm going to include all the files) //These are the DLL Files. ifndef TestDLL_H define TestDLL_H extern "C" { // Returns a + b __declspec(dllexport) double Add(double a, double b); // Returns a - b __declspec(dllexport) double Subtract(double a, double b); // Returns a * b __declspec(dllexport) double Multiply(double a, double b); // Returns a / b // Throws DivideByZeroException if b is 0 __declspec(dllexport) double Divide(double a, double b); } endif //.cpp include "test.h" include using namespace std; extern double __cdecl Add(double a, double b) { return a + b; } extern double __cdecl Subtract(double a, double b) { return a - b; } extern double __cdecl Multiply(double a, double b) { return a * b; } extern double __cdecl Divide(double a, double b) { if (b == 0) { throw new invalid_argument("b cannot be zero!"); } return a / b; } //C# Program using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Runtime.InteropServices; namespace ConsoleApplication1 { class Program { [DllImport("SDES.dll")] public static extern void SimulateGameDLL(int a, int b); static void Main(string[] args) { SimulateGameDLL(1, 2); //Error here... } } } Anyone have any idea's what I may be missing in my program? Let me know if I missed some code or if you have any questions.

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  • Passing an object as a parameter to a windows service

    - by user220723
    Is there some way to pass an object to a windows service? I know the method myServiceController.Star(string[] arg) but i need to pass a more complex object than a string array. Actually, i don't need the object to be passed as a parameter, what i really needs is that the service can use an object created in a windows forms application. I've tried using System.Web.Script.Serialization.JavaScriptSerializer.Serialize method to convert the object into a Json but i couldn't because the object contains a circular reference. I also tried using pointers, but i couldn't becouse it is a managed type object. Any idea what can i do?

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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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  • Help Using NetuserAdd() and NetLocalGroupAddMembers() in C++

    - by Brett Powell
    So I think I almost got it. I create my dummy account with one function, and wrote a second function to add it to the Remote Desktop group. Problem is, the Administrator account is the one logged in, so I am not sure how to specify what account to add to the group. Here is my code... The user is being created properly... void AddRDPUser() { USER_INFO_1 ui; DWORD dwLevel = 1; DWORD dwError = 0; NET_API_STATUS nStatus; ui.usri1_name = L"BrettXFactor"; ui.usri1_password = L"XfactorsServer96"; ui.usri1_priv = USER_PRIV_USER; ui.usri1_home_dir = NULL; ui.usri1_comment = NULL; ui.usri1_flags = UF_SCRIPT; ui.usri1_script_path = NULL; nStatus = NetUserAdd(NULL, dwLevel, (LPBYTE)&ui, &dwError); } But I dont know how to specify to add them to this group since they are not logged in. Any help would be appreciated void AddToGroup() { LOCALGROUP_MEMBERS_INFO_3 lgmi3; DWORD dwLevel = 3; DWORD totalEntries = 1; NET_API_STATUS nStatus; LPCWSTR TargetGroup = L"Remote Desktop Users"; LPSTR sBuffer = NULL; memset(sBuffer, 0, 255); DWORD nBuffSize = sizeof(sBuffer); if(GetUserNameEx(NameDnsDomain, sBuffer, &nBuffSize)==0) { Msg("Failed to add User to Group\n"); return; } LPWSTR user_name = (LPWSTR)sBuffer; lgmi3.lgrmi3_domainandname = user_name; nStatus = NetLocalGroupAddMembers(NULL, TargetGroup, 3, (LPBYTE)&lgmi3, totalEntries); }

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  • How can I use CssResources in UiBinder a generated Cell?

    - by confile
    I want to generate a Cell for a CellWidget with the UiBinder (UiRenderer). What I did to generate the cell is in MyCell.java: public class MyCell implements AbstractCell<MyDto> { public interface Resources extends ClientBundle { @Source({Css.DEFAULT_CSS }) Css css(); } public interface Css extends CssResource { String DEFAULT_CSS = "test/MyStyle.css"; String test(); } interface MyUiRenderer extends UiRenderer { void render(SafeHtmlBuilder sb, String name, SafeStyles styles); } private static MyUiRenderer renderer = GWT.create(MyUiRenderer.class); Resources resources = GWT.create(Resources.class); @Override public void render(SafeHtmlBuilder safeHtmlBuilder, MyDto model) { SafeStyles style = SafeStylesUtils.fromTrustedString(resources.css().test().toString()); renderer.render(safeHtmlBuilder, model.getName(), style); } } My MyCell.ui.xml file looks like this: <!DOCTYPE ui:UiBinder SYSTEM "http://dl.google.com/gwt/DTD/xhtml.ent"> <ui:UiBinder xmlns:ui='urn:ui:com.google.gwt.uibinder'> <ui:with field="name" type="java.lang.String" /> <ui:with field='styles' type='com.google.gwt.safecss.shared.SafeStyles'/> <div style="{styles}"><ui:text from="{name}" /></div> </ui:UiBinder> MyStyle.css: .test { background-color: red; font-size: 20px; display: flex; ... } When I run my code I get the following error: [DEBUG] [mobile] - Rebinding test.client.app.MyCell.MyUiRenderer [DEBUG] [mobile] - Invoking generator com.google.gwt.uibinder.rebind.UiBinderGenerator [ERROR] [mobile] - java.lang.String required, but {styles} returns com.google.gwt.safecss.shared.SafeStyles: <div style='{styles}'> (:9) [ERROR] [mobile] - Deferred binding failed for 'test.client.app.MyCell.MyUiRenderer'; expect subsequent failures [ERROR] [mobile] - (GWT.java:72) 2014-06-08 17:15:05,214 [FATAL] Uncaught Exception: Then I tried to this: in my UiBinder but it does not work. How can I use css style from a CssResource in my UiRenderer?

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  • GLSL point inside box test

    - by wcochran
    Below is a GLSL fragment shader that outputs a texel if the given texture coord is inside a box, otherwise a color is output. This just feels silly and the there must be a way to do this without branching? uniform sampler2D texUnit; varying vec4 color; varying vec2 texCoord; void main() { vec4 texel = texture2D(texUnit, texCoord); if (any(lessThan(texCoord, vec2(0.0, 0.0))) || any(greaterThan(texCoord, vec2(1.0, 1.0)))) gl_FragColor = color; else gl_FragColor = texel; } Below is a version without branching, but it still feels clumsy. What is the best practice for "texture coord clamping"? uniform sampler2D texUnit; varying vec4 color; varying vec4 labelColor; varying vec2 texCoord; void main() { vec4 texel = texture2D(texUnit, texCoord); bool outside = any(lessThan(texCoord, vec2(0.0, 0.0))) || any(greaterThan(texCoord, vec2(1.0, 1.0))); gl_FragColor = mix(texel*labelColor, color, vec4(outside,outside,outside,outside)); } I am clamping texels to the region with the label is -- the texture s & t coordinates will be between 0 and 1 in this case. Otherwise, I use a brown color where the label ain't. Note that I could also construct a branching version of the code that does not perform a texture lookup when it doesn't need to. Would this be faster than a non-branching version that always performed a texture lookup? Maybe time for some tests...

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  • How to get a float value the pointer points to?

    - by aleluja
    Hello, In my app, i've created the TList type list where i store the pointers to 1 string and 2 float(real) values for every 3 items. aList.Add(@sName); //string aList.Add(@x1); //float aList.Add(@x2); //float Then, i want to get the values out from the list, but i could only do that for string sStr := string(lList.items[i]); But i couldn't get the float values as a := real(lList...) will result in an invalid typecast error. So what do i do to get the float values? Of course i have a question if that string casting will actually give me the string value. I'm not good at pointer stuff so i don't know how to do it.

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  • Function calls in virtual machine killing performance

    - by GenTiradentes
    I wrote a virtual machine in C, which has a call table populated by pointers to functions that provide the functionality of the VM's opcodes. When the virtual machine is run, it first interprets a program, creating an array of indexes corresponding to the appropriate function in the call table for the opcode provided. It then loops through the array, calling each function until it reaches the end. Each instruction is extremely small, typically one line. Perfect for inlining. The problem is that the compiler doesn't know when any of the virtual machine's instructions are going to be called, as it's decided at runtime, so it can't inline them. The overhead of function calls and argument passing is killing the performance of my VM. Any ideas on how to get around this?

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  • need an empty XML while unmarshalling a JAXB annotated class

    - by sswdeveloper
    I have a JAXB annotated class Customer as follows @XmlRootElement(namespace = "http://www.abc.com/customer") public class Customer{ private String name; private Address address; @XmlTransient private HashSet set = new HashSet<String>(); public String getName(){ return name; } @XmlElement(name = "Name", namespace = "http://www.abc.com/customer" ) public void setName(String name){ this.name = name; set.add("name"); } public String getAddress(){ return address; } @XmlElement(name = "Address", namespace = "http://www.abc.com/customer") public void setAddress(Address address){ this.address = address; set.add("address"); } public HashSet getSet(){ return set; } } I need to return an empty XML representing this to the user, so that he may fill the necesary values in the XML and send a request So what I require is : <Customer> <Name></Name> <Address></Address> </Customer> If i simply create an empty object Customer cust = new Customer() ; marshaller.marshall(cust,sw); all I get is the toplevel element since the other fields of the class are unset. What can I do to get such an empty XML? I tried adding the nillable=true annotation to the elements however, this returns me an XML with the xsi:nil="true" which then causes my unmarshaller to ignore this. How do I achieve this?

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  • throwing exception from APCProc crashes program

    - by lazy_banana
    I started to do some research on how terminate a multithreaded application properly and I found those 2 post(first, second) about how to use QueueUserAPC to signal other threads to terminate. I thought I should give it a try, and the application keeps crashing when I throw the exception from the APCProc. Code: #include <stdio.h> #include <windows.h> class ExitException { public: char *desc; DWORD exit_code; ExitException(char *desc,int exit_code): desc(desc), exit_code(exit_code) {} }; //I use this class to check if objects are deconstructed upon termination class Test { public: char *s; Test(char *s): s(s) { printf("%s ctor\n",s); } ~Test() { printf("%s dctor\n",s); } }; DWORD CALLBACK ThreadProc(void *useless) { try { Test t("thread_test"); SleepEx(INFINITE,true); return 0; } catch (ExitException &e) { printf("Thread exits\n%s %lu",e.desc,e.exit_code); return e.exit_code; } } void CALLBACK exit_apc_proc(ULONG_PTR param) { puts("In APCProc"); ExitException e("Application exit signal!",1); throw e; return; } int main() { HANDLE thread=CreateThread(NULL,0,ThreadProc,NULL,0,NULL); Sleep(1000); QueueUserAPC(exit_apc_proc,thread,0); WaitForSingleObject(thread,INFINITE); puts("main: bye"); return 0; } My question is why does this happen? I use mingw for compilation and my OS is 64bit. Can this be the reason?I read that you shouldn't call QueueApcProc from a 32bit app for a thread which runs in a 64bit process or vice versa, but this shouldn't be the case.

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  • efficient sort with custom comparison, but no callback function

    - by rob
    I have a need for an efficient sort that doesn't have a callback, but is as customizable as using qsort(). What I want is for it to work like an iterator, where it continuously calls into the sort API in a loop until it is done, doing the comparison in the loop rather than off in a callback function. This way the custom comparison is local to the calling function (and therefore has access to local variables, is potentially more efficient, etc). I have implemented this for an inefficient selection sort, but need it to be efficient, so prefer a quick sort derivative. Has anyone done anything like this? I tried to do it for quick sort, but trying to turn the algorithm inside out hurt my brain too much. Below is how it might look in use. // the array of data we are sorting MyData array[5000], *firstP, *secondP; // (assume data is filled in) Sorter sorter; // initialize sorter int result = sortInit (&sorter, array, 5000, (void **)&firstP, (void **)&secondP, sizeof(MyData)); // loop until complete while (sortIteration (&sorter, result) == 0) { // here's where we do the custom comparison...here we // just sort by member "value" but we could do anything result = firstP->value - secondP->value; }

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  • In order to bypass a website's login screen, can you load a link with a username and password?

    - by Jeff
    I am relatively new to web development, and I was hoping I could get some pointers about the feasibility of a feature I would like to implement. Is it possible to have a url link that you can click on, that can contain login credentials for the website it is linking to, so as to bypass that websites login screen? In other words, can I make a link from my website to facebook, that would allow me to login right in to my facebook, from any computer? Meaning, if I don't have cookies to store my login info in, is it possible to login still? This is just a conceptual question, so any help would be appreciated! Thanks!

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  • Why we can't we overload "=" using friend function?

    - by ashish-sangwan
    Why it is not allowed to overload "=" using friend function? I have written a small program but it is giving error. class comp { int real; int imaginary; public: comp(){real=0; imaginary=0;} void show(){cout << "Real="<<real<<" Imaginary="<<imaginary<<endl;} void set(int i,int j){real=i;imaginary=j;} friend comp operator=(comp &op1,const comp &op2); }; comp operator=(comp &op1,const comp &op2) { op1.imaginary=op2.imaginary; op1.real=op2.real; return op1; } int main() { comp a,b; a.set(10,20); b=a; b.show(); return 0; } The compilation gives the following error :- [root@dogmatix stackoverflow]# g++ prog4.cpp prog4.cpp:11: error: ‘comp operator=(comp&, const comp&)’ must be a nonstatic member function prog4.cpp:14: error: ‘comp operator=(comp&, const comp&)’ must be a nonstatic member function prog4.cpp: In function ‘int main()’: prog4.cpp:25: error: ambiguous overload for ‘operator=’ in ‘b = a’ prog4.cpp:4: note: candidates are: comp& comp::operator=(const comp&) prog4.cpp:14: note: comp operator=(comp&, const comp&)

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