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  • Dll Import : Unable to find Entry Point "fnMultiply" in DLL "ImportDLL"

    - by user662285
    I am trying to use DLLImport for using Win32 dll method in C#. Win32 dll C++ // .h file #ifdef IMPORTDLL_EXPORTS #define IMPORTDLL_API __declspec(dllexport) #else #define IMPORTDLL_API __declspec(dllimport) #endif // This class is exported from the ImportDLL.dll class IMPORTDLL_API CImportDLL { public: CImportDLL(void); // TODO: add your methods here. int Add(int a , int b); }; extern IMPORTDLL_API int nImportDLL; IMPORTDLL_API int fnImportDLL(void); IMPORTDLL_API int fnMultiply(int a,int b); // .cpp file // ImportDLL.cpp : Defines the exported functions for the DLL application. // #include "stdafx.h" #include "ImportDLL.h" // This is an example of an exported variable IMPORTDLL_API int nImportDLL=0; // This is an example of an exported function. IMPORTDLL_API int fnImportDLL(void) { return 42; } IMPORTDLL_API int fnMultiply(int a , int b) { return (a*b); } Once i build this i get ImportDLL.dll Now i create Windows Application and add this dll in debug folder and try to use this method using DLLImport [DllImport("ImportDLL.dll")] public static extern int fnMultiply(int a, int b); And I try to call this in C# int a = fnMultiply(5, 6); // This line gives error Unable to find an entry point Can any body tell what i am missing? Thanks.

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  • hint and textview with right gravity and a singleline

    - by codeScriber
    I've opened a bug but i was wondering if anyone encountered this issue and knows a workaround. If you define a text view with a hint inside it, give it right gravity (android:gravity="right") then if you define android:singleLine=true or android:maxLines="1" or android:scrollHorizonatally="true" you don't see the hint. removing the right gravity returns the hint to the left side, removing all the tree params i mentioned above puts the hint on the right side. i want my hint on the right, but i need a single horizontal line... here's the sample layout that doesn't show the hint: <?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="fill_parent" android:layout_height="wrap_content" android:padding="5dp"> <EditText android:layout_width="fill_parent" android:layout_gravity="center_vertical|right" android:layout_height="wrap_content" android:layout_margin="6dp" android:textSize="16sp" android:paddingRight="5dp" android:id="@+id/c" android:gravity="right" android:hint="hello!!!" android:scrollHorizontally="true" android:maxLines="1" android:singleLine="true"/> </LinearLayout> i checked on 1.6 and 2.1 emulators and it reproduces 100%, i'm prettysure it's a bug, i don't see the connection between single line and the hint.... what's more the hint got it's own layout in the TextView (mLayout and mHintLayout both exists, in onDraw if the text length is 0 mHintLayout if mHint is not null is used).

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  • compiler directive defensive programming for adding ints to nsmuatablearray FMDB/EGODB

    - by johndpope
    I would like to throw a warning message when users try to add an int to an nsmutablearray basically any insert statement that includes values that are not nsstring / nsnumber cause run time crashes. It's exactly the same crash you get when you type %@ instead of %d NSLog(int); The crash is ok, but I want to throw a friendly 'FATAL' message to user. so far I have this try catch with isKindOfClass NSObject but ints are slipping through. #define FATAL_MSG "FATAL: object is not an NSObject subclass. Are you using int? use [NSNumber numberWithInt:1] \n" #define VAToArray(firstarg) ({\ NSMutableArray* valistArray = [NSMutableArray array];\ id obj = nil;\ va_list arguments;\ va_start(arguments, sql);\ @try { \ while ((obj = va_arg(arguments, id))) {\ if([obj isKindOfClass:[NSObject class]]) [valistArray addObject:obj];\ else printf(FATAL_MSG); \ }\ } \ @catch(NSException *exception){ \ printf(FATAL_MSG); \ } \ va_end(arguments);\ valistArray;\ }) - (void)test:(NSString*)sql,... { NSLog(@"VAToArray :%@",VAToArray(sql)); } // then call this [self test:@"str",@"test",nil]; when I call this [self test:@"str",2,nil]; throw the error message.

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  • Scheme: what are the benefits of letrec?

    - by Ixmatus
    While reading "The Seasoned Schemer" I've begun to learn about letrec. I understand what it does (can be duplicated with a Y-Combinator) but the book is using it in lieu of recurring on the already defined function operating on arguments that remain static. An example of an old function using the defined function recurring on itself (nothing special): (define (substitute new old lat) (cond ((null? l) '()) ((eq? (car l) old) (cons new (substitute new old (cdr l)))) (else (cons (car l) (substitute new old (cdr l)))))) Now for an example of that same function but using letrec: (define (substitute new old lat) (letrec ((replace (lambda (l) (cond ((null? l) '()) ((eq? (car l) old) (cons new (replace (cdr l)))) (else (cons (car l) (replace (cdr l)))))))) (replace lat))) Aside from being slightly longer and more difficult to read I don't know why they are rewriting functions in the book to use letrec. Is there a speed enhancement when recurring over a static variable this way because you don't keep passing it?? Is this standard practice for functions with arguments that remain static but one argument that is reduced (such as recurring down the elements of a list)? Some input from more experienced Schemers/LISPers would help!

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  • Using ember-resource with couchdb - how can i save my documents?

    - by Thomas Herrmann
    I am implementing an application using ember.js and couchdb. I choose ember-resource as database access layer because it nicely supports nested JSON documents. Since couchdb uses the attribute _rev for optimistic locking in every document, this attribute has to be updated in my application after saving the data to the couchdb. My idea to implement this is to reload the data right after saving to the database and get the new _rev back with the rest of the document. Here is my code for this: // Since we use CouchDB, we have to make sure that we invalidate and re-fetch // every document right after saving it. CouchDB uses an optimistic locking // scheme based on the attribute "_rev" in the documents, so we reload it in // order to have the correct _rev value. didSave: function() { this._super.apply(this, arguments); this.forceReload(); }, // reload resource after save is done, expire to make reload really do something forceReload: function() { this.expire(); // Everything OK up to this location Ember.run.next(this, function() { this.fetch() // Sub-Document is reset here, and *not* refetched! .fail(function(error) { App.displayError(error); }) .done(function() { App.log("App.Resource.forceReload fetch done, got revision " + self.get('_rev')); }); }); } This works for most cases, but if i have a nested model, the sub-model is replaced with the old version of the data just before the fetch is executed! Interestingly enough, the correct (updated) data is stored in the database and the wrong (old) data is in the memory model after the fetch, although the _rev attribut is correct (as well as all attributes of the main object). Here is a part of my object definition: App.TaskDefinition = App.Resource.define({ url: App.dbPrefix + 'courseware', schema: { id: String, _rev: String, type: String, name: String, comment: String, task: { type: 'App.Task', nested: true } } }); App.Task = App.Resource.define({ schema: { id: String, title: String, description: String, startImmediate: Boolean, holdOnComment: Boolean, ..... // other attributes and sub-objects } }); Any ideas where the problem might be? Thank's a lot for any suggestion! Kind regards, Thomas

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  • templete class c++

    - by inna karpasas
    hi! i try to design a templete for my universty project. i wrote the follwing cod: #ifndef _LinkedList_H_ #define _LinkedList_H_ #include "Link.h" #include <ostream> template <class L>//error one class LinkedList { private: Link<L> *pm_head; Link<L> * pm_tail; int m_numOfElements; Link<L>* FindLink(L * dataToFind); public: LinkedList(); ~LinkedList(); int GetNumOfElements(){return m_numOfElements;} bool Add( L * data); L *FindData(L * data); template <class L> friend ostream & operator<<(ostream& os,const LinkedList<L> listToprint);//error two L* GetDataOnTop(); bool RemoveFromHead(); L* Remove(L * toRemove); this templete uses the link class templete #ifndef _Link_H_ #define _Link_H_ template <class T>//error 3 class Link { private: T* m_data; Link* m_next; Link* m_prev; public: Link(T* data); ~Link(void); bool Link::operator ==(const Link& other)const; /*getters*/ Link* GetNext()const {return m_next;} Link* GetPrev()const {return m_prev;} T* GetData()const {return m_data;} //setters void SetNext(Link* next) {m_next = next;} void SetPrev(Link* prev) {m_prev = prev;} void SetData(T* data) {m_data = data;} }; error one: shadows template parm class L' error two:declaration ofclass L' error three: shadows template parm `class T' i dont understand what is the problem. i can relly usr your help thank you :)

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  • UIImageView subclass with CGRectIntersectsRect - help!

    - by Flafla2
    The title of this question should be pretty self explanatory. I am making an app that involves multiple UIImageViews that serve the same purpose. They are merely different sizes. Anyway, I decided that the best solution was to make UIImageView subclasses, link the subcalsses in IB, and work from there. My code should explain this better - #define kPausedStatePaused 1 #define kPausedStatePlay 2 #import "Game.h" #import "ScoreSystem.h" @interface Doctor : UIImageView { } @end @interface Ground : UIImageView { } @end @interface Wall : UIImageView { } @end @interface Electric_Wire : UIImageView { } @end @implementation Game /* // The designated initializer. Override if you create the controller programmatically and want to perform customization that is not appropriate for viewDidLoad. - (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil { if (self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil]) { // Custom initialization } return self; } */ /* // Implement viewDidLoad to do additional setup after loading the view, typically from a nib. - (void)viewDidLoad { [super viewDidLoad]; } */ - (IBAction)pause { UIAlertView *pause = [[UIAlertView alloc] initWithTitle:@"Pause" message:nil delegate:self cancelButtonTitle:@"Quit" otherButtonTitles:@"Play", nil]; [pause show]; [pause release]; pauseint = kPausedStatePaused; } - (void)viewDidAppear { pauseint = kPausedStatePlay; } - (void)loop { Doctor *doctorview; Ground *groundview; if (CGRectIntersectsRect(doctorview, groundview)) { } } - (void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex { if ([alertView.title isEqual:@"Pause"]) { if(buttonIndex == 0) [self dismissModalViewControllerAnimated:YES]; pauseint = kPausedStatePlay; } } // Override to allow orientations other than the default portrait orientation. - (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation { // Return YES for supported orientations return (interfaceOrientation == UIInterfaceOrientationLandscapeRight); } - (void)didReceiveMemoryWarning { // Releases the view if it doesn't have a superview. [super didReceiveMemoryWarning]; // Release any cached data, images, etc that aren't in use. } - (void)viewDidUnload { // Release any retained subviews of the main view. // e.g. self.myOutlet = nil; } - (void)dealloc { [super dealloc]; } @end Unsurprisingly, Xcode gave me an "incompatible type for CGRectIntersectsRect" error.

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  • RBG to CbyCr conversion code

    - by user1446688
    I am wondering why this code does not work. Basically it is supposed to convert between RGB and CbYCr. When I convert from RGB to CbYCr then back to RGB I do not get the original RGB values. What is wrong with this code? #define MIN(a,b) (((a)<(b))?(a):(b)) #define MAX(a,b) (((a)(b))?(a):(b)) struct _rgb { int R; int G; int B; }; typedef struct _rgb rgb; struct _cbycr { int Cb; int Y; int Cr; }; typedef struct _cbycr cbycr; void cbycr2rgb(rgb *c, double Y, double Cb, double Cr) { int r = (int)(Y + 1.40200 * (Cr - 0x80)); int g = (int)(Y - 0.34414 * (Cb - 0x80) - 0.71414 * (Cr - 0x80)); int b = (int)(Y + 1.77200 * (Cb - 0x80)); c->R = MAX(0, MIN(255, r)); c->G = MAX(0, MIN(255, g)); c->B = MAX(0, MIN(255, b)); } void rgb2cbycr(cbycr *c, int R, int G, int B) { c->Y = (int)(0.299 * R + 0.587 * G + 0.114 * B); c->Cb = (int)(-0.16874 * R - 0.33126 * G + 0.50000 * B); c->Cr =(int)(0.50000 * R - 0.41869 * G - 0.08131 * B); } int main() { cbycr _cbycr; rgb _rgb; _rgb.R = 50; _rgb.G = 50; _rgb.B = 50; rgb2cbycr(&_cbycr, _rgb.R, _rgb.G, _rgb.B); cbycr2rgb(&_rgb, _cbycr.Y, _cbycr.Cb, _cbycr.Cr); printf("rgb=%d %d %d\n", _rgb.R, _rgb.G, _rgb.B); return 0; } output: rgb=0 185 0

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  • Dynamic stack allocation in C++

    - by Poni
    I want to allocate memory on the stack. Heard of _alloca / alloca and I understand that these are compiler-specific stuff, which I don't like. So, I came-up with my own solution (which might have it's own flaws) and I want you to review/improve it so for once and for all we'll have this code working: /*#define allocate_on_stack(pointer, size) \ __asm \ { \ mov [pointer], esp; \ sub esp, [size]; \ }*/ /*#define deallocate_from_stack(size) \ __asm \ { \ add esp, [size]; \ }*/ void test() { int buff_size = 4 * 2; char *buff = 0; __asm { // allocate mov [buff], esp; sub esp, [buff_size]; } // playing with the stack-allocated memory for(int i = 0; i < buff_size; i++) buff[i] = 0x11; __asm { // deallocate add esp, [buff_size]; } } void main() { __asm int 3h; test(); } Compiled with VC9. What flaws do you see in it? Me for example, not sure that subtracting from ESP is the solution for "any kind of CPU". Also, I'd like to make the commented-out macros work but for some reason I can't.

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  • Fluently setting C# properties and chaining methods

    - by John Feminella
    I'm using .NET 3.5. We have some complex third-party classes which are automatically generated and out of my control, but which we must work with for testing purposes. I see my team doing a lot of deeply-nested property getting/setting in our test code, and it's getting pretty cumbersome. To remedy the problem, I'd like to make a fluent interface for setting properties on the various objects in the hierarchical tree. There are a large number of properties and classes in this third-party library, and it would be too tedious to map everything manually. My initial thought was to just use object initializers. Red, Blue, and Green are properties, and Mix() is a method that sets a fourth property Color to the closest RGB-safe color with that mixed color. Paints must be homogenized with Stir() before they can be used. Bucket b = new Bucket() { Paint = new Paint() { Red = 0.4; Blue = 0.2; Green = 0.1; } }; That works to initialize the Paint, but I need to chain Mix() and other methods to it. Next attempt: Create<Bucket>(Create<Paint>() .SetRed(0.4) .SetBlue(0.2) .SetGreen(0.1) .Mix().Stir() ) But that doesn't scale well, because I'd have to define a method for each property I want to set, and there are hundreds of different properties in all the classes. Also, C# doesn't have a way to dynamically define methods prior to C# 4, so I don't think I can hook into things to do this automatically in some way. Third attempt: Create<Bucket>(Create<Paint>().Set(p => { p.Red = 0.4; p.Blue = 0.2; p.Green = 0.1; }).Mix().Stir() ) That doesn't look too bad, and seems like it'd be feasible. Is this an advisable approach? Is it possible to write a Set method that works this way? Or should I be pursuing an alternate strategy?

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  • emacs -- keybind questions

    - by user565739
    I have successfully used Ctrl+Shift+Up ' Ctrl+Shift+down ' Ctrl+Shift+left' Ctrl+Shift+Right to different commands. But when I tried to use Ctrl+s to the command save-buffer and Ctrl+Shift+s, which is equivalent to Ctrl+S, to another command, it has some problem. save-buffer works fine, but when I type Ctrl+Shift+s, it excute the command save-buffer. I used Ctrl+q to find the control sequences of Ctrl+s and Ctrl+Shift+S, I get the same result, which is ^S. I expect that I will get ^s for Ctrl+s, but it doesn't. Anyone knows the reason? Another queston is: I use Ctrl+c for the command killing-ring-save. In this case, all commands (which are of large number) begin with Ctrl+c don't work now. Is there a way to replace the prefix Ctrl+c by another customized prefix? I may pose my question in the wrong direction. I use ctrl+c as killing-ring-save. It works fine in emacs (no mode). But if I open a .c file (C-mode), then when I type Ctrl+c, it waits me to type another key. I think in this case, ctrl+c is regarded as a prefix. In this case, I need the following modifications: Using a custom defined prefix, say Ctrl+a, as Ctrl+c ; Remove the prefix Ctrl+c ; Using Ctrl+c as killing-ring-save. I add the following to my ~/.emacs : (defun my-c-initialization-hook () (define-key c-mode-base-map (kbd "C-a") mode-specific-map) (define-key c-mode-base-map (kbd "C-c") 'kill-ring-save)) (add-hook 'c-initialization-hook 'my-c-initialization-hook) But this doesn't work. Ctrl+c is still regarded as a prefix, so I can't use it as kill-ring-save. Furthermore, if I type Ctrl+a Ctrl+c, it said it's not defined. (I thought it will have the same result as I type Ctrl+c Ctrl+c)

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  • Kernighan & Ritchie word count example program in a functional language

    - by Frank
    I have been reading a little bit about functional programming on the web lately and I think I got a basic idea about the concepts behind it. I'm curious how everyday programming problems which involve some kind of state are solved in a pure functional programing language. For example: how would the word count program from the book 'The C programming Language' be implemented in a pure functional language? Any contributions are welcome as long as the solution is in a pure functional style. Here's the word count C code from the book: #include <stdio.h> #define IN 1 /* inside a word */ #define OUT 0 /* outside a word */ /* count lines, words, and characters in input */ main() { int c, nl, nw, nc, state; state = OUT; nl = nw = nc = 0; while ((c = getchar()) != EOF) { ++nc; if (c == '\n') ++nl; if (c == ' ' || c == '\n' || c = '\t') state = OUT; else if (state == OUT) { state = IN; ++nw; } } printf("%d %d %d\n", nl, nw, nc); }

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  • Highlighting correctly in an emacs major mode

    - by Paul Nathan
    Hi, I am developing an emacs major mode for a language (aka mydsl). However, using the techniques on xahlee's site doesn't seem to be working for some reason (possibly older emacs dialect..) The key issues I am fighting with are (1) highlighting comments is not working and (2), the use of regexp-opt lines is not working. I've reviewed the GNU manual and looked over cc-mode and elisp mode... those are significantly more complicated than I need. ;;;Standard # to newline comment ;;;Eventually should also have %% to %% multiline block comments (defun mydsl-comment-dwim (arg) "comment or uncomment" (interactive "*P") (require 'newcomment) (let ((deactivate-mark nil) (comment-start "#") (comment-end "") comment-dwim arg))) (defvar mydsl-events '("reservedword1" "reservedword2")) (defvar mydsl-keywords '("other-keyword" "another-keyword")) ;;Highlight various elements (setq mydsl-hilite '( ; stuff between " ("\"\\.\\*\\?" . font-lock-string-face) ; : , ; { } => @ $ = are all special elements (":\\|,\\|;\\|{\\|}\\|=>\\|@\\|$\\|=" . font-lock-keyword-face) ( ,(regexp-opt mydsl-keywords 'words) . font-lock-builtin-face) ( ,(regexp-opt mydsl-events 'words) . font-lock-constant-face) )) (defvar mydsl-tab-width nil "Width of a tab for MYDSL mode") (define-derived-mode mydsl-mode fundamental-mode "MYDSL mode is a major mode for editing MYDSL files" ;Recommended by manual (kill-all-local-variables) (setq mode-name "MYDSL script") (setq font-lock-defaults '((mydsl-hilite))) (if (null mydsl-tab-width) (setq tab-width mydsl-tab-width) (setq tab-width default-tab-width) ) ;Comment definitions (define-key mydsl-mode-map [remap comment-dwim] 'mydsl-comment-dwim) (modify-syntax-entry ?# "< b" mydsl-mode-syntax-table) (modify-syntax-entry ?\n "> b" mydsl-mode-syntax-table) ;;A gnu-correct program will have some sort of hook call here. ) (provide 'mydsl-mode)

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  • How do I convert an AMD module from a singleton to an instance?

    - by Jamie Ide
    I'm trying to convert a working Durandal view model module from a singleton to an instance. The original working version followed this pattern: define(['knockout'], function(ko) { var vm = { activate: activate, companyId: null; company: ko.observable({}) }; return vm; function activate(companyId) { vm.companyId = companyId; //get company data then vm.company(data); } } The new version exports a function so that I get a new instance on every request... define(['knockout'], function(ko) { var vm = function() { activate = activate; companyId = null; company = ko.observable({}); }; return vm; function activate(companyId) { vm.companyId = companyId; //get company data then vm.company(data); } } The error I'm getting is "object function () [...function signature...] has no method company on the line vm.company(data);. What am I doing wrong? Why can I set the property but can't access the knockout observable? How should I refactor the original code so that I get a new instance on every request? My efforts to simplify the code for this question hid the actual problem. My real code was using Q promises and calling two methods with Q.All. Since Q is in the global namespace, it couldn't resolve my viewmodel after converting to a function. Passing the view model to the methods called by Q resolved the problem.

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  • confused about how to use JSON in C#

    - by Josh
    The answer to just about every single question about using C# with json seems to be "use JSON.NET" but that's not the answer I'm looking for. the reason I say that is, from everything I've been able to read in the documentation, JSON.NET is basically just a better performing version of the DataContractSerializer built into the .net framework... Which means if I want to deserialize a JSON string, I have to define the full, strongly-typed class for EVERY request I might have. so if I have a need to get categories, posts, authors, tags, etc, I have to define a new class for every one of these things. This is fine if I built the client and know exactly what the fields are, but I'm using someone else's api, so I have no idea what the contract is unless I download a sample response string and create the class manually from the JSON string. Is that the only way it's done? Is there not a way to have it create a kind of hashtable that can be read with json["propertyname"]? Finally, if I do have to build the classes myself, what happens when the API changes and they don't tell me (as twitter seems to be notorious for doing)? I'm guessing my entire project will break until I go in and update the object properties... So what exactly is the general workflow when working with JSON? And by general I mean library-agnostic. I want to know how it's done in general, not specifically to a target library... I hope that made sense, this has been a very confusing area to get into... thanks!

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  • eclipse show errors but compiles when external makefile

    - by Anthony
    I have some c++ code using CImg and Eigen libraries. At the c++ code I define a plugin like this #define cimg_plugin1 "my_plugin.h" #include "CImg.h" The plugin contains many method definitions that are used at the c++ code. I also have a makefile that when called from the command line (./make), allows me to compile everything, and generates an executable. I want to import this code into a new Eclipse project, and I do it so: NewProjectC++ projectmakefile projectempty project unmark "Use default location", and select the folder containing my code at the filesystem ProjectpropertiesC/C++ Buildunmark "Use default build command" and set it to use my makefile Also in project propertiesC/C++ GeneralPaths and SymbolsAdd paths to folders containing Eigen and CImg Rebuild index Clean project Restart eclipse When I build the project, eclipse tells me I have more than 1000 errors in "my_plugin.h", but it is capable to generate the executable. Even though, I would like to get rid of this errors, because they are annoying. Also, if I want to open the declaration of CImg methods used at the plugin, I can't. I know it has been asked before, but any of the solutions I found were satisfactory for me (most of them enumerated at the previous list). The sources I visited are the following, and I would be really happy if you find and tell me others I didn't see. Eclipse shows errors but project compile fine eclipse C project shows errors (Symbol could not be resolved) but it compiles Eclipse CDT shows some errors, but the project is successfully built http://www.eclipse.org/forums/index.php/t/247954/

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  • implementing cryptographic algorithms, specifically the key expansion part

    - by masseyc
    Hey, recently I picked up a copy of Applied Cryptography by Bruce Schneier and it's been a good read. I now understand how several algorithms outlined in the book work, and I'd like to start implementing a few of them in C. One thing that many of the algorithms have in common is dividing an x-bit key, into several smaller y-bit keys. For example, blowfish's key, X, is 64-bits, but you are required to break it up into two 32-bit halves; Xl and Xr. This is where I'm getting stuck. I'm fairly decent with C, but I'm not the strongest when it comes to bitwise operators and the like. After some help on IRC, I managed to come up with these two macros: #define splitup(a, b, c) {b = a >> 32; c = a & 0xffffffff; } #define combine(a, b, c) {a = (c << 32) | a;} Where a is 64 bits and b and c are 32 bits. However, the compiler warns me about the fact that I'm shifting a 32 bit variable by 32 bits. My questions are these: what's bad about shifting a 32-bit variable 32 bits? I'm guessing it's undefined, but these macros do seem to be working. Also, would you suggest I go about this another way? As I said, I'm fairly familiar with C, but bitwise operators and the like still give me a headache.

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  • How best to deal with warning c4305 when type could change?

    - by identitycrisisuk
    I'm using both Ogre and NxOgre, which both have a Real typedef that is either float or double depending on a compiler flag. This has resulted in most of our compiler warnings now being: warning C4305: 'argument' : truncation from 'double' to 'Ogre::Real' When initialising variables with 0.1 for example. Normally I would use 0.1f but then if you change the compiler flag to double precision then you would get the reverse warning. I guess it's probably best to pick one and stick with it but I'd like to write these in a way that would work for either configuration if possible. One fix would be to use #pragma warning (disable : 4305) in files where it occurs, I don't know if there are any other more complex problems that can be hidden by not having this warning. I understand I would push and pop these in header files too so that they don't end up spreading across code. Another is to create some macro based on the accuracy compiler flag like: #if OGRE_DOUBLE_PRECISION #define INIT_REAL(x) (x) #else #define INIT_REAL(x) static_cast<float>( x ) #endif which would require changing all the variable initialisation done so far but at least it would be future proof. Any preferences or something I haven't thought of?

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  • Mutual class instances in C++

    - by SepiDev
    Hi guys. What is the issue with this code? Here we have two files: classA.h and classB.h classA.h: #ifndef _class_a_h_ #define _class_a_h_ #include "classB.h" class B; //???? class A { public: A() { ptr_b = new B(); //???? } virtual ~A() { if(ptr_b) delete ptr_b; //???? num_a = 0; } int num_a; B* ptr_b; //???? }; #endif //_class_a_h_ classB.h: #ifndef _class_b_h_ #define _class_b_h_ #include "classA.h" class A; //???? class B { public: B() { ptr_a = new A(); //???? num_b = 0; } virtual ~B() { if(ptr_a) delete ptr_a; //???? } int num_b; A* ptr_a; //???? }; #endif //_class_b_h_ when I try to compile it, the compiler (g++) says: classB.h: In constructor ‘B::B()’: classB.h:12: error: invalid use of incomplete type ‘struct A’ classB.h:6: error: forward declaration of ‘struct A’ classB.h: In destructor ‘virtual B::~B()’: classB.h:16: warning: possible problem detected in invocation of delete operator: classB.h:16: warning: invalid use of incomplete type ‘struct A’ classB.h:6: warning: forward declaration of ‘struct A’ classB.h:16: note: neither the destructor nor the class-specific operator delete will be called, even if they are declared when the class is defined.

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  • Is it possible to create a python iterator over pre-defined mutable data?

    - by Wilduck
    I might be doing this wrong, if I am, let me know, but I'm curious if the following is possible: I have a class that holds a number of dictionaries, each of which pairs names to a different set of objects of a given class. For example: items = {"ball" : ItemInstance1, "sword" : ItemInstance2} people = {"Jerry" : PersonInstance1, "Bob" : PersonInstance2, "Jill" : PersonInstance3} My class would then hold the current items and people that are availible, and these would be subject to change as the state changes: Class State: def __init__(self, items, people): self.items = items self.people = people I would like to define a iter() and next() method such that it iterates through all of the values in its attributes. My first question is whether or not this is possible. If it is, will it be able to support a situation as follows: I define items and people as above then: state = State(items, people) for names, thing in state: print name + " is " + thing.color items[cheese] = ItemInstance3 for names, thing in state: print name + " weighs " + thing.weight While I feel like this would be usefull in the code I have, I don't know if it's either possible or the right approach. Everything I've read about user defined iterators has suggested that each instance of them is one use only.

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  • Creating an appropriate index for a frequently used query in SQL Server

    - by Slauma
    In my application I have two queries which will be quite frequently used. The Where clauses of these queries are the following: WHERE FieldA = @P1 AND (FieldB = @P2 OR FieldC = @P2) and WHERE FieldA = @P1 AND FieldB = @P2 P1 and P2 are parameters entered in the UI or coming from external datasources. FieldA is an int and highly on-unique, means: only two, three, four different values in a table with say 20000 rows FieldB is a varchar(20) and is "almost" unique, there will be only very few rows where FieldB might have the same value FieldC is a varchar(15) and also highly distinct, but not as much as FieldB FieldA and FieldB together are unique (but do not form my primary key, which is a simple auto-incrementing identity column with a clustered index) I'm wondering now what's the best way to define an index to speed up specifically these two queries. Shall I define one index with... FieldB (or better FieldC here?) FieldC (or better FieldB here?) FieldA ... or better two indices: FieldB FieldA and FieldC FieldA Or are there even other and better options? What's the best way and why? Thank you for suggestions in advance!

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  • SQLAlchemy & Complex Queries

    - by user356594
    I have to implement ACL for an existing application. So I added the a user, group and groupmembers table to the database. I defined a ManyToMany relationship between user and group via the association table groupmembers. In order to protect some ressources of the app (i..e item) I added a additional association table auth_items which should be used as an association table for the ManyToMany relationship between groups/users and the specific item. item has following columns: user_id -- user table group_id -- group table item_id -- item table at least on of user_id and group_id columns are set. So it's possible to define access for a group or for a user to a specific item. I have used the AssociationProxy to define the relationship between users/groups and items. I now want to display all items which the user has access to and I have a really hard time doing that. Following criteria are used: All items which are owned by the user should be shown (item.owner_id = user.id) All public items should be shown (item.access = public) All items which the user has access to should be shown (auth_item.user_id = user.id) All items which the group of the user has access to should be shown. The first two criteria are quite straightforward, but I have a hard time doing the 3rd one. Here is my approach: clause = and_(item.access == 'public') if user is not None: clause = or_(clause,item.owner == user,item.users.contains(user),item.groups.contains(group for group in user.groups)) The third criteria produces an error. item.groups.contains(group for group in user.groups) I am actually not sure if this is a good approach at all. What is the best approach when filtering manytomany relationships? How I can filter a manytomany relationship based on another list/relationship? Btw I am using the latest sqlalchemy (6.0) and elixir version Thanks for any insights.

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  • Initialize Static Array of Structs in C

    - by russell_h
    I implementing a card game in C. There are lots of types of cards and each has a bunch of information, including some actions that will need to be individually scripted associated with it. Given a struct like this (and I'm not certain I have the syntax right for the function pointer) struct CARD { int value; int cost; // This is a pointer to a function that carries out actions unique // to this card int (*do_actions) (struct GAME_STATE *state, int choice1, int choice2); }; I would like to initialize a static array of these, one for each card. I'm guessing this would look something like this int do_card0(struct GAME_STATE *state, int choice1, int choice2) { // Operate on state here } int do_card1(struct GAME_STATE *state, int choice1, int choice2) { // Operate on state here } extern static struct cardDefinitions[] = { {0, 1, do_card0}, {1, 3, do_card1} }; Will this work, and am I going about this the right way at all? I'm trying to avoid huge numbers of switch statements. Do I need to define the 'do_cardN' functions ahead of time, or is there some way to define them inline in the initialization of the struct (something like a lambda function in python)? I'll need read-only access to cardDefinitions from a different file - is 'extern static' correct for that? I know this is a lot of questions rolled into one but I'm really a bit vague about how to go about this. Thanks.

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  • No idea how to solve SICP exercise 1.11

    - by Javier Badia
    This is not homework. Exercise 1.11: A function f is defined by the rule that f(n) = n if n<3 and f(n) = f(n - 1) + 2f(n - 2) + 3f(n - 3) if n 3. Write a procedure that computes f by means of a recursive process. Write a procedure that computes f by means of an iterative process. Implementing it recursively is simple enough. But I couldn't figure out how to do it iteratively. I tried comparing with the Fibonacci example given, but I didn't know how to use it as an analogy. So I gave up (shame on me) and Googled for an explanation, and I found this: (define (f n) (if (< n 3) n (f-iter 2 1 0 n))) (define (f-iter a b c count) (if (< count 3) a (f-iter (+ a (* 2 b) (* 3 c)) a b (- count 1)))) After reading it, I understand the code and how it works. But what I don't understand is the process needed to get from the recursive defintion of the function to this. I don't get how the code formed in someone's head. Could you explain the thought process needed to arrive at the solution?

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  • C# Event Handlers Using an Enum

    - by Jimbo
    I have a StatusChanged event that is raised by my object when its status changes - however, the application needs to carry out additional actions based on what the new status is. e.g If the new status is Disconnected, then it must update the status bar text and send an email notification. So, I wanted to create an Enum with the possible statuses (Connected, Disconnected, ReceivingData, SendingData etc.) and have that sent with the EventArgs parameter of the event when it is raised (see below) Define the object: class ModemComm { public event CommanderEventHandler ModemCommEvent; public delegate void CommanderEventHandler(object source, ModemCommEventArgs e); public void Connect() { ModemCommEvent(this, new ModemCommEventArgs ModemCommEventArgs.eModemCommEvent.Connected)); } } Define the new EventArgs parameter: public class ModemCommEventArgs : EventArgs{ public enum eModemCommEvent { Idle, Connected, Disconnected, SendingData, ReceivingData } public eModemCommEvent eventType { get; set; } public string eventMessage { get; set; } public ModemCommEventArgs(eModemCommEvent eventType, string eventMessage) { this.eventMessage = eventMessage; this.eventType = eventType; } } I then create a handler for the event in the application: ModemComm comm = new ModemComm(); comm.ModemCommEvent += OnModemCommEvent; and private void OnModemCommEvent(object source, ModemCommEventArgs e) { } The problem is, I get a 'Object reference not set to an instance of an object' error when the object attempts to raise the event. Hoping someone can explain in n00b terms why and how to fix it :)

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