Search Results

Search found 113 results on 5 pages for 'johannes ruuska'.

facebook twitter digg google delicious technorati stumbleupon myspace wordpress linkedin gmail igoogle windows live tumblr viadeo yahoo buzz yahoo mail yahoo bookmarks favorites email print

Page 4/5 | < Previous Page | 1 2 3 4 5  | Next Page >

  • Function with parameter type that has a copy-constructor with non-const ref chosen?

    - by Johannes Schaub - litb
    Some time ago I was confused by the following behavior of some code when I wanted to write a is_callable<F, Args...> trait. Overload resolution won't call functions accepting arguments by non-const ref, right? Why doesn't it reject in the following because the constructor wants a Test&? I expected it to take f(int)! struct Test { Test() { } // I want Test not be copyable from rvalues! Test(Test&) { } // But it's convertible to int operator int() { return 0; } }; void f(int) { } void f(Test) { } struct WorksFine { }; struct Slurper { Slurper(WorksFine&) { } }; struct Eater { Eater(WorksFine) { } }; void g(Slurper) { } void g(Eater) { } // chooses this, as expected int main() { // Error, why? f(Test()); // But this works, why? g(WorksFine()); } Error message is m.cpp: In function 'int main()': m.cpp:33:11: error: no matching function for call to 'Test::Test(Test)' m.cpp:5:3: note: candidates are: Test::Test(Test&) m.cpp:2:3: note: Test::Test() m.cpp:33:11: error: initializing argument 1 of 'void f(Test)' Can you please explain why one works but the other doesn't?

    Read the article

  • XMLEncoder and PersistenceDelegate

    - by Johannes Rössel
    I'm trying to use XMLEncoder to write an object graph (tree in my case) to a file. However, one class contained in it is not actually a Java bean and I don't particularly like making its guts publicly accessible. It's accessed more like a list and has appropriate add methods. I've already written a custom PersistenceDelegate to deal with that. However, is there any way for XMLEncoder to pick it up on its own or do I really need to add it whenever I use an encoder to write a graph that may contain said class?

    Read the article

  • Combining two UPDATE Commands - Performance ?

    - by Johannes
    If I want to update two rows in a MySQL table, using the following two command: UPDATE table SET Col = Value1 WHERE ID = ID1 UPDATE table SET Col = Value2 WHERE ID = ID2` I usually combine them into one command, so that I do not to have to contact the MySQL server twice from my C client: UPDATE table SET Col = IF( ID = ID1 , Value1 , Value2) WHERE ID=ID1 OR ID=ID2 Is this really a performance gain? Background Information: I am using a custom made fully C written high-performance heavily loaded webserver.

    Read the article

  • C callback functions defined in an unnamed namespace?

    - by Johannes Schaub - litb
    Hi all. I have a C++ project that uses a C bison parser. The C parser uses a struct of function pointers to call functions that create proper AST nodes when productions are reduced by bison: typedef void Node; struct Actions { Node *(*newIntLit)(int val); Node *(*newAsgnExpr)(Node *left, Node *right); /* ... */ }; Now, in the C++ part of the project, i fill those pointers class AstNode { /* ... */ }; class IntLit : public AstNode { /* ... */ }; extern "C" { Node *newIntLit(int val) { return (Node*)new IntLit(val); } /* ... */ } Actions createActions() { Actions a; a.newIntLit = &newIntLit; /* ... */ return a; } Now the only reason i put them within extern "C" is because i want them to have C calling conventions. But optimally, i would like their names still be mangled. They are never called by-name from C code, so name mangling isn't an issue. Having them mangled will avoid name conflicts, since some actions are called like error, and the C++ callback function has ugly names like the following just to avoid name clashes with other modules. extern "C" { void uglyNameError(char const *str) { /* ... */ } /* ... */ } a.error = &uglyNameError; I wondered whether it could be possible by merely giving the function type C linkage extern "C" void fty(char const *str); namespace { fty error; /* Declared! But i can i define it with that type!? */ } Any ideas? I'm looking for Standard-C++ solutions.

    Read the article

  • Objective-C subclasses question

    - by Johannes Jensen
    I have a class called Level, which is a subclass of NSObject. Then I have a class called Level_1_1 which is a subclass of Level. Is it allowed to type like Level* aLevel = [Level_1_1 alloc]; instead of Level_1_1* theLevel = [Level_1_1 alloc]; ? :) I try it and I don't get any warnings, just wondering if it's okay to do?

    Read the article

  • Examples of ISO C++ code that is not valid C++/CLI

    - by Johannes Schaub - litb
    I've seen contradictory answers on the internet with regard to whether C++/CLI is a superset of C++ or not. The accepted answer on this question claims that "technically no", but doesn't provide an examples of non-C++/CLI code that conforms to ISO C++. Another answer on that question cites a book that says the opposite. So, can you please provide accurate answers with example code that fails on C++/CLI or cite a trusted source (MSDN for example) on this matter? I had someone this topic come up today and thought I would like to inform myself, but I didn't find any clear answer elsewhere!

    Read the article

  • Why do C++ streams use char instead of unsigned char?

    - by Johannes Schaub - litb
    I've always wondered why the C++ Standard library has instantiated basic_[io]stream and all its variants using the char type instead of the unsigned char type. char means (depending on whether it is signed or not) you can have overflow and underflow for operations like get(), which will lead to implementation-defined value of the variables involved. Another example is when you want to output a byte, unformatted, to an ostream using its put function. Any ideas? Note: I'm still not really convinced. So if you know the definitive answer, you can still post it indeed.

    Read the article

  • MEMORY(HEAP) vs. InnoDB in a Read and Write Environment

    - by Johannes
    I want to program a real-time application using MySQL. It needs a small table (less than 10000 rows) that will be under heavy read (scan) and write (update and some insert/delete) load. I am really speaking of 10000 updates or selects per second. These statements will be executed on only a few (less than 10) open mysql connections. The table is small and does not contain any data that needs to be stored on disk. So I ask which is faster: InnoDB or MEMORY (HEAP)? My thoughts are: Both engines will probably serve SELECTs directly from memory, as even InnoDB will cache the whole table. What about the UPDATEs? (innodb_flush_log_at_trx_commit?) My main concern is the locking behavior: InnoDB row lock vs. MEMORY table lock. Will this present the bottleneck in the MEMORY implementation? Thanks for your thoughts!

    Read the article

  • iPhone: Cocos2d how to make a sequence

    - by Johannes Jensen
    I have two logos, which I want to come in after each other. I'd like to use CCFadeIn and CCFadeOut. I have Logo1, and then I want it to CCFadeIn, then I want it to stay for 2 seconds, then make it fade out using CCFadeOut, and then make Logo2 CCFadeIn for 1 second, stay for 2 seconds and then go away during 1 second with CCFadeOut. How I would make this I'm not completely sure. I can't seem to find a way to make a CCAction fire a method (let's say -finishedFadingInLogo1:), so I don't know how to do this. Any ideas?

    Read the article

  • PowerShell function arguments: Can the first one be optional first?

    - by Johannes Rössel
    I have an advanced function in PowerShell, which roughly looks like this: function Foo { [CmdletBinding] param ( [int] $a = 42, [int] $b ) } The idea is that it can be run with either two, one or no arguments. However, the first argument to become optional is the first one. So the following scenarios are possible to run the function: Foo a b # the normal case, both a and b are defined Foo b # a is omitted Foo # both a and b are omitted However, normally PowerShell tries to fit the single argument into a. So I thought about specifying the argument positions explicitly, where a would have position 0 and b position 1. However, to allow for only b specified I tried putting a into a parameter set. But then b would need a different position depending on the currently-used parameter set. Any ideas how to solve this properly? I'd like to retain the parameter names (which aren't a and b actually), so using $args is probably a last resort. I probably could define two parameter sets, one with two mandatory parameters and one with a single optional one, but I guess the parameter names have to be different in that case, then, right?

    Read the article

  • iPhone App Store Distribution questions

    - by Johannes Jensen
    I would like to enroll my company in to the iPhone Developer Program for $99. I have a few questions, which I can't really find an answer to, because Apple aren't very detailed in their pages unless you actually registered. So here goes: 1.) Is the $99 paid yearly? 2.) It says when distributing free apps there's no fee, but if I want to distribute a $0.99 app, what is the fee then? Is it huge? Or..? 3.) Can I keep track of how many people bought my app anytime? 4.) Is there a page on the internet where I can read more about app store distribution that explains almost all the info I need to know? (Apple doesn't satisfy me on this) Thanks

    Read the article

  • mercurial setup for Visual Studio 2008 projects

    - by Johannes
    What is a good setup for .hgignore file when working with Visual Studio 2008? I mostly develop on my own, only occasionly I clone the repository for somebody else to work on it. I'm thinking about obj folders, .suo, .sln, .user files etc.. Can they just be included or are there file I shouldn't include? Thanks! p.s.: at the moment I do the following : ignore all .pdb files and all obj folders. # regexp syntax. syntax: glob *.pdb syntax: regexp /obj/

    Read the article

  • Recursive templates: compilation error under g++

    - by Johannes
    Hi, I am trying to use templates recursively to define (at compile-time) a d-tuple of doubles. The code below compiles fine with Visual Studio 2010, but g++ fails and complains that it "cannot call constructor 'point<1::point' directly". Could anyone please shed some light on what is going on here? Many thanks, Jo #include <iostream> #include <utility> using namespace std; template <const int N> class point { private: pair<double, point<N-1> > coordPointPair; public: point() { coordPointPair.first = 0; coordPointPair.second.point<N-1>::point(); } }; template<> class point<1> { private: double coord; public: point() { coord= 0; } }; int main() { point<5> myPoint; return 0; }

    Read the article

  • Catch Id (INT AUTO INCREMENT) of a Record after INSERT INTO Statement

    - by Johannes
    This is my first time I use MySQL as datastorage for my C# Application, as I've seen that there is no UNIQUEIDENTIFIER type as in SQL server I decieded to use INT with AUTO_INCREMENT, my problem is now if I execute a INSERT, how may I get the ID of the Record I just added. My quick and dirty solution has been to execute a SELECT MAX(ID) FROM table Statement. But this doesn't seem consistent. I belive there is a better solution something like mysql_insert_id() (PHP). Any Idea how to resolve this in C#?

    Read the article

  • MEMORY(HEAP) vs. InnoDB in a Read and Write Envirnment

    - by Johannes
    I want to programm a real-time application using MySQL. It needs a small table (less than 10000 rows) that will be under heavy read (scan) and write (update and some insert/delete) load. I am really speaking of 10000 updates or selects per second. These statements will be executed on only a few (less than 10) open mysql connections. The table is small and does not contain any data that needs to be stored on disk. So I ask which is faster: InnoDB or MEMORY (HEAP)? My thoughts are: Both enginges will probably serve SELECTs directly from memory, as even InnoDB will cache the whole table. What about the UPDATAEs? (innodb_flush_log_at_trx_commit?) My main concern is the locking behavior: InnoDB row lock vs. MEMORY table lock. Will this present the bottleneck in the MEMORY implementation? Thanks for your thoughts!

    Read the article

  • Concurrency problem with arrays (Java)

    - by Johannes
    For an algorithm I'm working on I tried to develop a blacklisting mechanism that can blacklist arrays in a specific way: If "1, 2, 3" is blacklisted "1, 2, 3, 4, 5" is also considered blacklisted. I'm quite happy with the solution I've come up with so far. But there seem to be some serious problems when I access a blacklist from multiple threads. The method "contains" (see code below) sometimes returns true, even if an array is not blacklisted. This problem does not occur if I only use one thread, so it most likely is a concurrency problem. I've tried adding some synchronization, but it didn't change anything. I also tried some slightly different implementations using java.util.concurrent classes. Any ideas on how to fix this? public class Blacklist { private static final int ARRAY_GROWTH = 10; private final Node root = new Node(); private static class Node{ private volatile Node[] childNodes = new Node[ARRAY_GROWTH]; private volatile boolean blacklisted = false; public void blacklist(){ this.blacklisted = true; this.childNodes = null; } } public void add(final int[] array){ synchronized (root) { Node currentNode = this.root; for(final int edge : array){ if(currentNode.blacklisted) return; else if(currentNode.childNodes.length <= edge) { currentNode.childNodes = Arrays.copyOf(currentNode.childNodes, edge + ARRAY_GROWTH); } if(currentNode.childNodes[edge] == null) { currentNode.childNodes[edge] = new Node(); } currentNode = currentNode.childNodes[edge]; } currentNode.blacklist(); } } public boolean contains(final int[] array){ synchronized (root) { Node currentNode = this.root; for(final int edge : array){ if(currentNode.blacklisted) return true; else if(currentNode.childNodes.length <= edge || currentNode.childNodes[edge] == null) return false; currentNode = currentNode.childNodes[edge]; } return currentNode.blacklisted; } } }

    Read the article

  • Send copy of class to view class so it can render him? ( iPhone )

    - by Johannes Jensen
    I'm making a game for the iPhone, and I have a class called Robot. Then I have a class called View, which renders everything. I want to send a copy of my Robot, which I defined in my ViewController, and I send it to gameView (which is View *gameView), like this: robot = [Robot new]; [gameView setRobot: [robot copy]]; I tried to make a copy but that didn't work, I could also do it with a pointer to Robot (&robot) but sometimes it just crashes ? I tried this in my View.h @interface definition: @property (copy) Robot* robot; but I get the error /RobotsAdventure/Classes/View.h:24: error: setter '-robot' argument type does not match property type :/ Help? I'm pretty new at this, heh.

    Read the article

  • iPhone - Drawing 2D with OpenGL ES, fast and simple.

    - by Johannes Jensen
    I'm going to make a game for the iPhone, and I'm mostly going to be using images. I've read that using Quartz only is slow for actual games with high frame rates, so I was wondering if you guys had any good ideas for using OpenGL for rendering a game scene? I'm going to be using a lot of images, and I want to be able to freely rotate them. I've looked at Apple's examples GLSprite and GLPaint, but I don't really see anything I could use. All I want to do is be able to render images at specific positions, and want to be able to rotate them. I'm a noob at OpenGL, but I know Quartz.

    Read the article

  • XNA how to organize code with game components (managers)

    - by Johannes
    XNA If I have a button class, and I have a buttonManager class that manages what buttons to be drawn to the screen depending on what the current game state is (main menu, in game, etc), how do I organize my code so that when I click on a button, it takes the user to a different screen. (ex. options menu, ingame). To be more specific, if I were to put the check to see if the user clicks on the button within the buttonManager how would I have the game switch and run the actual game (which is in an entire different class)? Main gameclass buttonManager game component (adds buttons) Button class

    Read the article

  • Setting up a view to draw to in Objective-C (iPhone) ?

    - by Johannes Jensen
    Okay, so, I'm all new to iPhone and stuff, but I'm not even at programming, I have many years of experience with ActionScript 2.0 and 3.0, I want to set up a view, that I can also pass variables to. The view is gonna draw everything with Quartz. I tried to make another game where I tried to add a pointer to a NSMutableArray to the view class, but it didn't work cause I didn't know how to store an actual class. I wanted to do like: [myView setNeedsDisplay]; but I had to do [(View*)self.view setNeedsDisplay]; didn't really work out in the end... Okay, so now I got: - (void) viewDidLoad { [super viewDidLoad]; viewClass = [[View class] retain]; gameView = [[[viewClass alloc] initWithFrame: CGRectZero] retain]; [gameView setNeedsDisplay]; } This is in my drawInContext:context, which is fired by drawRect: Also, my drawRect does [self drawInContext: UIGraphicsGetCurrentContext()]; CGContextSetStrokeColorWithColor(context, [[UIColor blackColor] CGColor]); CGContextSetLineWidth(context, 3.0); CGContextSetLineCap(context, kCGLineCapRound); CGContextSetLineJoin(context, kCGLineJoinRound); CGMutablePathRef aPath = CGPathCreateMutable(); CGPathMoveToPoint(aPath, nil, 5, 5); CGPathAddLineToPoint(aPath, nil, 45, 43); CGContextAddPath(context, aPath); CGContextStrokePath(context); Nothing happens. Help? Oh yeah, I get this error: : invalid context for each time I use those functions. :[ Thanks!

    Read the article

  • What's the bug in the following code ?

    - by Johannes
    #include <iostream> #include <algorithm> #include <vector> #include <boost/array.hpp> #include <boost/bind.hpp> int main() { boost::array<int, 4> a = {45, 11, 67, 23}; std::vector<int> v(a.begin(), a.end()); std::vector<int> v2; std::transform(v.begin(), v.end(), v2.begin(), boost::bind(std::multiplies<int>(), _1, 2)); std::copy(v2.begin(), v2.end(), std::ostream_iterator<int>(std::cout, " ")); } When run, this gives a creepy segmentation fault. Please tell me where I'm going wrong.

    Read the article

facebook twitter digg google delicious technorati stumbleupon myspace wordpress linkedin gmail igoogle windows live tumblr viadeo yahoo buzz yahoo mail yahoo bookmarks favorites email print

< Previous Page | 1 2 3 4 5  | Next Page >