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• Call function by pointer and set parametrs in memory block

  - by Ellesmess Glain

  Hi, I've little problem : I'm solving problem with calling function by pointer and passing to it parameters in continuous memory block. My goal is to have function named e.g CallFunc(void * func,void *params, unsigned int param_length); that I'll send function pointer, pointer to function's parameters and eventually parameters length and this calling function will call passed function with it's parameters. I will like write this in C/C++, but if somebody has idea, how this resolve in other language, that supports DLL generation and exportet functions, it will be fine too. Thanks for answers, Ellesmess P.S. I'm sorry about my English, but I'm Czech, thanks :o)

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• lua function as argument in C

  - by Nil

  I'm going to pass a function to another function which should operate with the passed function. For example: handler(fun1("foo",2)) handler(fun2(1e-10)) The handler is something like calling the passed function many times. I'm going to bind handler, fun1, fun2 to C-functions. fun1 and fun2 are going to return some user data with a pointer to some cpp-class so that I can further recover which function was it. The problem now is that fun1 and fun2 are going to be called before passed to handler. But I don't need this, what I need is the kind of function and its parameters. However, I should be able to call fun1 and fun2 alone without handler: fun1("bar",3) fun2(1e-5) Is it possible to get the context the function is called from? While typing the question, I realized I could do following handler(fun1, "foo",2); handler(fun2, 1e-10);

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• Multithreaded SDL error in C++

  - by wyatt

  I'm building a program in C++, using SDL, and am occasionally receiving this error: * glibc detected * ./assistant: double free or corruption (!prev) It's difficult to replicate, so I can't find exactly what's causing it, but I just added a second thread to the program, and neither thread run on its own seems to cause the error. The threads don't share any variables, though they both run the functions SDL_BlitSurface and SDL_Flip. Could running these concurrently throw up such an error, or am I barking up the wrong tree? If this is the cause, should I simply throw a mutex around all SDL calls? Thanks

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• Just how much do I want to make virtual?

  - by Alex

  I am writing an abstract superclass where literally every method is going to be overridden. There is some default functionality I could implement, but most of the time it's enough to leave the implementation to the subclass writer. Since just about every method is going to be overwritten, how much should I make virtual and how much should I just leave as regular methods? In the current incarnation, everything is virtual, but I still haven't let this loose to anyone to use, so the design is flexible. What advantages/disadvantages are there to virtual functions? Links to good reading material about this would be appreciated.

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• Callback Timer function in C++

  - by user3596609

  I am trying to implement a callback timer function in C++ which should do a callback after a timeout. I am listening on a socket and then waiting for messages on it. so if I have something like getMessages() and I want to pass the timer function in it as an argument. So how can it be implemented that after the receive of a message, the timer is started and the callback happens if there is a timeout before the next messages arrives. I am new to callback functions. Any help is greatly appreciated. Thanks!

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• Why does OpenGL have to completely break backwards compatablity?

  - by directx

  I'm not sure if this only applies to JOGL or the entire OpenGL project in general. But there seems to be a vast difference between versions 3.x and 2.x; Code that works on one version will not work on another. It looks to me like the library designers intentionally renamed various classes, packages, and functions just to screw up the existing code. I've never seen anything like this before. The problem is I'm not sure which library to use now, and when looking at code it's not so easy to figure out whether it's supposed to run on 2.x or 3.x.

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• sequencing function calls in javascript - are callbacks the only way?

  - by tim

  I read through various threads like this one for example. But it really escapes me how to accomplish the following: I have 4 functions, and want them happen one after another in sequence. Notice they are in incorrect order, to get my point across. I want the result that will output "1, 2, 3, 4' function firstFunction(){ // some very time consuming asynchronous code... console.log('1'); } function thirdFunction(){ // definitely dont wanna do this until secondFunction is finished console.log('3'); } function secondFunction(){ // waits for firstFunction to be completed console.log('2'); } function fourthFunction(){ // last function, not executed until the other 3 are done. console.log('4'); } I tried to figure out callbacks but am getting lost :( Isn't there some simple way to do this? Like looping through an array...

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• Changing the context of a self-executing function

  - by TaylorMac

  This code is copied directly from: http://www.bennadel.com/blog/2264-Changing-The-Execution-Context-Of-Your-Self-Executing-Function-Blocks-In-JavaScript.htm // Set the singleton value to the return value of the self- // executing function block. var singleton = (function(){ // Declare a private variable. var message = "Stop playing with your context!"; this.getMessage = function(){ return( message ); }; // Return this object reference. return( this ); }).call( {} ); // alert the singleton message. alert( "Message:", singleton.getMessage()); ?My thought is that I can use this to better contain the variables and functions in my programs. However, when I try to run the code in a JSfiddle: http://jsfiddle.net/xSKHh/ It does not return the message. What am I missing?

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• Implementing an iterator over binary tree using C++ 11

  - by user1459339

  I would like to create an iterator over the binary tree so as to be able to use range-based for loop. I understand I ought to implement the begin() and end() function first. Begin should probably point to the root. According to the specification, however, the end() functions returns "the element following the last valid element". Which element (node) is that? Would it not be illegal to point to some "invalid" place? The other thing is the operator++. What is the best way to return "next" element in tree? I just need some advice to begin with this programming.

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• What open source C/C++ audio compression options are there besides LAME MP3?

  - by Ole Jak

  Are there any C/C++ open source audio encoder besides LAME MP3? It doesn't need to be exactly mp3 format, I need a "compressed digital audio file". I do not want to use Lame because it is too big while no programmer can answer a simple question on it (share simple but easily downloadable and readable project containing only needed 2 simple functions... So I'm tired of searching for help with it.. I need something fresh powerful but more readable than this lib I found (mp3stego) ) "I don't want LAME because I am a fighter with its monopoly" Haha..

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• Play Framework Form "fold" method naming rationale

  - by oym

  Play Framework's (2.x) Form class has a method called fold who's usage is indicated as: anyForm.bindFromRequest().fold( f => redisplayForm(f), t => handleValidFormSubmission(t) ) Essentially, the first function parameter is what gets executed on binding failure, and the 2nd on binding success. To me it seems similar to the 'success' and 'error' callbacks of jquery's ajax function. My question is why did the Play developers call the method "fold"? As a disclaimer I am new to Scala, but I am failing to see the connection between this and the functional Scala fold operation. The only similarity is that it is a higher order function; but I don't see any combining that is taking place, nor does it delegate internally in its implementation to any of the Scala fold functions.

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• Why does the Win32-API have so many custom types?

  - by sub

  I'm new to the Win32 API and the many new types begin to confuse me. Some functions take 1-2 ints and 3 UINTS as arguments. Why can't they just use ints? What are UINTS? Then, there are those other types: DWORD LPCWSTR LPBOOL Again, I think the "primitive" C types would be enough - why introduce 100 new types? This one was a pain: WCHAR* I had to iterate through it and push_back every character to an std::string as there wasn't another way to convert it to one. Horrible. Why WCHAR? Why reinvent the wheel? They could have just used char* instead, or?

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• Method to register method to be called when event is raised

  - by zaidwaqi

  I have a Panel which contains 20 PictureBox controls. If a user clicks on any of the controls, I want a method within the Panel to be called. How do I do this? public class MyPanel : Panel { public MyPanel() { for(int i = 0; i < 20; i++) { Controls.Add(new PictureBox()); } } // DOESN'T WORK. // function to register functions to be called if the pictureboxes are clicked. public void RegisterFunction( <function pointer> func ) { foreach ( Control c in Controls ) { c.Click += new EventHandler( func ); } } } How do I implement RegisterFunction()? Also, if there are cool C# features that can make the code more elegant, please share.

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• Change notification in CouchDB when a field is set

  - by PartlyCloudy

  Hi, I'm trying to get notifications in a CouchDB change poll as soon as pre-defined field is set or changed. I've already had a look at filters that can be used for filtering change events(db/_changes?filter=myfilter). However, I've not yet found a way to include this temporal information, because you can only get the current version of the document in this filter functions. Is there any possibility to create such a filter? If it does not work, I could export my field to a separate database and the only poll for changes in that db, but I'd prefer to keep together my data for obvious reasons. Thanks in advance!

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• F# - Function with no arguments?

  - by Rubys

  When thinking in a functional mindset, given that functions are supposed to be pure, one can conclude any function with no arguments is basically just a value. However, reallity gets in the way, and with different inputs, I might not need a certain function, and if that function is computationally expensive, I'd like to not evaluate it if it's not needed. I found a workaround, using let func _ = ... and calling it with func 1 or whatever, but that feels very non-idiomatic and confusing to the reader. This boils down to one question: In F#, Is there a proper way to declare a function with zero arguments, without having it evaluated on declaration?

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• JavaScript prototype(ing) question

  - by OneNerd

  Trying to grasp Prototyping in Javascript. Trying to create my own namespace to extend the String object in JavaScript. Here is what I have so far (a snippet): var ns { alert: function() { alert (this); } } String.prototype.$ns = ns; As you can see, I am trying to place what will be a series of functions into the ns namespace. So I can execute a command like this: "hello world".$ns.alert(); But the problem is, the this doesn't seem to reference the text being sent (in this case, "hello world"). What I get is an alert box with the following: [object Object] Not having a full grasp of the object-oriented nature of JavaScript, I am at a loss, but I am guessing I am missing something simple. Does anyone know how to achieve this? Thanks -

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• Call inner function of jQuery-Plugin-function?

  - by faileN

  Hello Everyone, I've written an jQuery-Plugin, which I want to use as Object. So I declared some functions within the plugin, which I want to call from any other location, just like an object with methods. Is that even possible? To keep it simple: (function( $ ){ $.fn.myPlugin = function(){ // Here I want methods... function foo() { // do something... } } })(jQuery); Then I want to call the inner function from outside the plugin like: $.myPlugin.foo(); But that doesn't seem to work. So is it even possible? Or are there any other solutions? I don't want to use an normal unrelated jQuery-Class for this purpose. Because this plugin should work together with some other jQuery-Plugins. Thank you

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• (g)Vim with version control like Eclipse

  - by Somebody still uses you MS-DOS

  I was an Eclipse user, now I have to use Vim in my machine. I used to "compare" a file I edited with a CVS repository to do merges an commit the files, using a context menu and my mouse. Is this possible in Vim? Opening a vimdiff for a file before commiting, and commit it from vim itself? And how is that supposed to work? I'm supposing I would be editing a file. Then, I want to see the modifications. I run vimdiff in gvim, and a new window (or buffer) is opened. I run the modifications, save what is applicable (using vimdiff commands), and commit running another command. Is this all transparent in vim? Do I have to keep getting out of vim to my terminal, or can all be done inside it? Do I need to use some plugins, or just really simple functions inside my vimrc?

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• between syntax, are there any equal function

  - by gcc

  /* char **mainp=malloc(sizeof(char *)*2); mainp[0]=malloc(sizeof(char)*300); mainp[1]=malloc(sizeof(char )*300); */ *I have some input about propositional calculus *After calculating some math funtion-removing paranthesis-changing"&" with ","-replacing "|" with"," I have >> (1) P,-Q,Q,-R is stored in mainp[0] R,A,P,B,F is stored in mainp[1] *My question is: Between comma , I have want to compare two pointer array. If there is any equal two or more functions(Q,-R is function representation) ,function which you will show me how to write must return int. According to example (1),function will return 1 (I expect like that) /*I have som thought://which function should I have use:*/ in for loop if( strspn(mainp[0][i])==1 ) increment d; continue; or in for loop srtcmp(mainp[0][i],mainp[1]);

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• AS3: Performance question calling an event function with null param

  - by adehaas

  Lately I needed to call a listener function without an actual listener like so: foo(null); private function foo(event:Event):void { //do something } So I was wondering if there is a significant difference regarding performance between this and using the following, in which I can prevent the null in calling the function without the listener, but am still able to call it with a listener as well: foo(); private function foo(event:Event = null):void { } I am not sure wether it is just a question of style, or actually bad practice and I should write two similar functions, one with and one without the event param (which seems cumbersome to me). Looking forward to your opinions, thx.

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• why include() don't allow to work setcookie?

  - by Syom

  i need to set cookies in my page, but it returns Warning: Cannot modify header information - headers already sent by (output started at /home1/bsam/public_html/24kadr/index.php:1) in /home1/bsam/public_html/24kadr/basic_login.php on line 35 on line 1 i have include 'basic_login.php'; but even if i remoove include, ir returns the same warning on session_start, or mysql_connect. so i think these all functions use header when calling, but what can i do? at least i need to connect to database, and just after it i need to use setcookie(). so what can i do? thanks

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• I just don't get why there is a glMatrixMode in OpenGL

  - by René Nyffenegger

  I just don't understand what OpenGL's glMatrixMode is for. As far as I can see, when glMatrixMode(GL_MODELVIEW) is called, it is followed by glVertex, glTranslate, glRotate and the like, that is, OpenGL commands that place some objects somewhere in the space. On the other hand, if glOrtho or glFrustum or gluProjection is called (ie how the placed objects are rendered), it has a preceeding call of glMatrixMode(GL_PROJECTION). I guess what I have written so far is an assumption on which someone will prove me wrong, but is not the point of using different *Matrix Mode*s exactly because there are different kinds of gl-functions: those concerned with placing objects and those with how the objects are rendered? So, if someone could shed some light on this issue, I'd certainly appreciate it.

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• login with users, groups and permissions

  - by Dan Bemowski

  OK, I have a set of tables that I want to use for my user logins. I am guessing that I need a separate model for each table in the database. My tables are as follows: Users - user information such as first and last name, groups_id, status, etc... groups - defines the user groups with id, name, description permissions - defines a list of permissions that a group can have permission_assignments - groups_id and permissions_id. many to many relationship table I am not sure how to go about populating an array that would contain the list of permissions that a user would have based on the group they are in after a successful login. Basically, a user belongs to a group, and the group gets assigned permissions. I want to then be able to validate functions/methods based on weather the logged in user has certain permissions. Any help is appreciated

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• How is this regex wrong?

  - by Spot

  I have a regex which I'm using to match user functions inside an IDE (Sublime). This matches what I want (the function name itself), but it also matches the first parentheses. Therefore the match is like follows: this._myFunction('content'); Notice the opening paran. Here is my expression: (?:[^\._])?([\w-]+)(?:[\(]){1} How can I exclude the opening paran from getting matched? . As a bonus question: How can I successfully not match the string: function, because as you can expect function( matches (not fun in JS). Thank you to anyone who can assist.

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• Issue with this function. The code is not executing.

  - by Tapha

  The function is supposed to update the values in the database. Here is the code: //Functions //Function to Update users networth function update_net($name) { //Get worth & balance at the time $sql_to_get_worth_balance = "SELECT * FROM user WHERE username = '$name'"; $sql_query = mysql_query($sql_to_get_worth_balance); while ($rows = mysql_fetch_assoc($sql_query)) { $worth = $rows['worth']; $balance_ = $rows['cash_balance']; } //Get net_worth now $new_net_worth = $worth + $balance; //Update net_worth $sql_for_new_worth = "UPDATE user SET net_worth = '$new_net_worth'"; $sql_worth_query = mysql_query($sql_worth); } It is used here: //Get username $username = $_SESSION['username']; if (isset($username)) { //Update networth $update_worth = update_net($username);

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