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• What OpenGL functions are not GPU accelerated?

  - by Xavier Ho

  I was shocked when I read this (from the OpenGL wiki): glTranslate, glRotate, glScale Are these hardware accelerated? No, there are no known GPUs that execute this. The driver computes the matrix on the CPU and uploads it to the GPU. All the other matrix operations are done on the CPU as well : glPushMatrix, glPopMatrix, glLoadIdentity, glFrustum, glOrtho. This is the reason why these functions are considered deprecated in GL 3.0. You should have your own math library, build your own matrix, upload your matrix to the shader. For a very, very long time I thought most of the OpenGL functions use the GPU to do computation. I'm not sure if this is a common misconception, but after a while of thinking, this makes sense. Old OpenGL functions (2.x and older) are really not suitable for real-world applications, due to too many state switches. This makes me realise that, possibly, many OpenGL functions do not use the GPU at all. So, the question is: Which OpenGL function calls don't use the GPU? I believe knowing the answer to the above question would help me become a better programmer with OpenGL. Please do share some of your insights.

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• Is there a way to log every gui event in Delphi?

  - by awmross

  The Delphi debugger is great for debugging linear code, where one function calls other functions in a predictable, linear manner, and we can step through the program line by line. I find the debugger less useful when dealing with event driven gui code, where a single line of code can cause new events to be trigerred, which may in turn trigger other events. In this situation, the 'step through the code' approach doesn't let me see everything that is going on. The way I usually solve this is to 1) guess which events might be part of the problem, then 2) add breakpoints or logging to each of those events. The problem is that this approach is haphazard and time consuming. Is there a switch I can flick in the debugger to say 'log all gui events'? Or is there some code I can add to trap events, something like procedure GuiEventCalled(ev:Event) begin log(ev); ev.call(); end The end result I'm looking for is something like this (for example): FieldA.KeyDown FieldA.KeyPress FieldA.OnChange FieldA.OnExit FieldB.OnEnter This would take all the guesswork out of Delphi gui debugging. I am using Delphi 2010

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• Inline function v. Macro in C -- What's the Overhead (Memory/Speed)?

  - by Jason R. Mick

  I searched Stack Overflow for the pros/cons of function-like macros v. inline functions. I found the following discussion: Pros and Cons of Different macro function / inline methods in C ...but it didn't answer my primary burning question. Namely, what is the overhead in c of using a macro function (with variables, possibly other function calls) v. an inline function, in terms of memory usage and execution speed? Are there any compiler-dependent differences in overhead? I have both icc and gcc at my disposal. My code snippet I'm modularizing is: double AttractiveTerm = pow(SigmaSquared/RadialDistanceSquared,3); double RepulsiveTerm = AttractiveTerm * AttractiveTerm; EnergyContribution += 4 * Epsilon * (RepulsiveTerm - AttractiveTerm); My reason for turning it into an inline function/macro is so I can drop it into a c file and then conditionally compile other similar, but slightly different functions/macros. e.g.: double AttractiveTerm = pow(SigmaSquared/RadialDistanceSquared,3); double RepulsiveTerm = pow(SigmaSquared/RadialDistanceSquared,9); EnergyContribution += 4 * Epsilon * (RepulsiveTerm - AttractiveTerm); (note the difference in the second line...) This function is a central one to my code and gets called thousands of times per step in my program and my program performs millions of steps. Thus I want to have the LEAST overhead possible, hence why I'm wasting time worrying about the overhead of inlining v. transforming the code into a macro. Based on the prior discussion I already realize other pros/cons (type independence and resulting errors from that) of macros... but what I want to know most, and don't currently know is the PERFORMANCE. I know some of you C veterans will have some great insight for me!!

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• Dynamic editor upload into web page. Need advice

  - by Andrew Florko

  Hello everybody, I am writing intranet site for tracking employees science activities in organization. There lots of editable information on each personal page (science degree, publications & so on) so I upload editor per request (user clicks "edit" and modal dialog with html editor: set of textboxes/comboboxes/autocomplete features & validation logic appears). Editor is html layout that is wrapped with jquery dialog plugin + some logic, written as javascript functions that should be invoked from the callee page (onsubmit, validate, afterLoad editor events). There are also attributes (editor preferrable with and height) that are passed to callee page also. Currently I send these functions & attribute as ... function onsubmit() { }; function validate() { } var width = 640; var height = 800 ... code that is embedded into the request page. Function calls and editor markup wrap with jquery plugin completed in the callee page. It works, but I have some try { call editor event handler } catch { } stuff in callee page (because not every editor provides these functions) and some attributes (editor width & height for instance) that are loaded as variables declared in javascript. Please, suggest, is there a better approach to build & use custom editors for my situation. Thank you in advance!

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• Turning a series of raw images into movie frames in Android

  - by Nicholas Killewald

  I've got an Android project I'm working on that, ultimately, will require me to create a movie file out of a series of still images taken with a phone's camera. That is to say, I want to be able to take raw image frames and string them together, one by one, into a movie. Audio is not a concern at this stage. Looking over the Android API, it looks like there are calls in it to create movie files, but it seems those are entirely geared around making a live recording from the camera on an immediate basis. While nice, I can't use that for my purposes, as I need to put annotations and other post-production things on the images as they come in before they get fed into a movie (plus, the images come way too slowly to do a live recording). Worse, looking over the Android source, it looks like a non-trivial task to rewire that to do what I want it to do (at least without touching the NDK). Is there any way I can use the API to do something like this? Or alternatively, what would be the best way to go about this, if it's even feasible on cell phone hardware (which seems to keep getting more and more powerful, strangely...)?

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• How to handle window closed in the middle of a long running operation gracefully?

  - by Marek

  We have the following method called directly from the UI thread: void DoLengthyProcessing() { DoStuff(); var items = DoMoreStuff(); //do even more stuff - 200 lines of code trimmed this.someControl.PrepareForBigThing(); //someControl is a big user control //additional 100 lines of code that access this.someControl this.someControl.Finish(items); } Many of the called methods call Application.DoEvents() (and they do so many times) (do not ask me why, this is black magic written by black magic programmers and it can not be changed because everyone is scared what the impact would be) and there is also an operation running on a background thread involved in the processing. As a result, the window is not fully nonresponsive and can be closed manually during the processing. The Dispose method of the form "releases" the someControl variable by setting it to null. As a result, in case the user closes the window during the lengthy process, a null reference exception is thrown. How to handle this gracefully without just catching and logging the exception caused by disposal? Assigning the someControl instance to a temporary variable in the beginning of the method - but the control contains many subcontrols with similar disposal scheme - sets them to null and this causes null reference exceptions in other place put if (this.IsDisposed) return; calls before every access of the someControl variable. - making the already nasty long method even longer and unreadable. in Closing event, just indicate that we should close and only hide the window. Dispose it at the end of the lengthy operation. This is not very viable because there are many other methods involved (think 20K LOC for a single control) that would need to handle this mechanism as well. How to most effectively handle window disposal (by user action) in the middle of this kind of processing?

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• Getting empty update rectangle in OnPaint after calling InvalidateRect on a layered window

  - by Shawn

  I'm trying to figure out why I've been getting an empty update rectangle when I call InvalidateRect on a transparent window. The idea is that I've drawn something on the window (it gets temporarily switched to have an alpha of 1/255 for the drawing), and then I switch it to full transparent mode (i.e. alpha of 0) in order to interact with the desktop & to be able to move the drawing around the screen on top of the desktop. When I try to move the drawing, I get its bounding rectangle & use it to call InvalidateRect, as such: InvalidateRect(m_hTarget, &winRect, FALSE); I've confirmed that the winRect is indeed correct, and that m_hTarget is the correct window & that its rectangle fully encompasses winRect. I get into the OnPaint handler in the class corresponding to m_hTarget, which is derived from a CWnd. In there, I create a CPaintDC, but when I try to access the update rectangle (dcPaint.m_ps.rcPaint) it's always empty. This rectangle gets passed to a function that determines if we need to update the screen (by using UpdateLayeredWindow in the case of a transparent window). If I hard-code a non-empty rectangle in here, the remaining code works correctly & I am able to move the drawing around the screen. I tried changing the 'FALSE' parameter to 'TRUE' in InvalidateRect, with no effect. I also tried using a standard CDC, and then using BeginPaint/EndPaint method in my OnPaint handler, just to ensure that CPaintDC wasn't doing something odd ... but I got the same results. The code that I'm using was originally designed for opaque windows. If m_hTarget corresponds to an opaque window, the same set of function calls results in the correct (i.e. non-empty) rectangle being passed to OnPaint. Once the window is layered, though, it doesn't seem to work right.

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• jQuery: AJAX call isn't updating page

  - by Cortopasta

  Thought I had a simple AJAX call using $.POST(), but apparently my function isn't firing, and nothing is updating :-/ Here is the call: $(".answerVerse ul li").click(function(){ var rank = $(this).removeClass("star_empty star_full star_highlight").attr("class"); var verse_id = $(this).parent().parent().find(".verseId").html(); var answer_id = $(this).parent().parent().find(".answerId").html(); var place = this; $.post("rank.php", { rank: rank, verse_id: verse_id, answer_id: answer_id },function(data){ $(place).parent().removeClass().addClass(data.newVerseRank); for (i=0;i<=5;i++) { $(".answerVerse ul."+i).each(function(){ $(".answerVerse ul."+i+" li."+i).prevAll().andSelf().removeClass("star_empty").addClass("star_full"); }); } }, "json"); }); And here is the PHP (rank.php) that it calls: require_once("dbcon.php"); $user = new user(); $user->updateVerseRank($_POST['verse_id'], $_POST['rank']); $user->getVerse($_POST['verse_id']); $user->getAnswer($_POST['answer_id']; $arr = array ('newVerseRank'=>htmlspecialchars(round($user->verse[3])),'newVerseVotes'=>htmlspecialchars(round($user->verse[4])),'newAnswerRank'=>htmlspecialchars($user->answer[3])); echo json_encode($arr); Why am I not updating the page? I know it's something dumb I'm doing seeing as how this is my first attempt at AJAX and JSON :-/ Just trying to learn

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• assembling an object graph without an ORM -- in the service layer or data layer?

  - by Hans Gruber

  At my current gig, our persistence layer uses IBatis going against SQL Server stored procedures (puke). IMHO, this approach has many disadvantages over the use of a "true" ORM such NHibernate or EF, but the one I'm trying to address here revolves around all the boilerplate code needed to map data from a result set into an object graph. Say I have the following DTO object graph I want to return to my presentation layer: IEnumerable<CustomerDTO> |--> IEnumerable<AddressDTO> |--> LatestOrderDTO The way I've implemented this is to have a discrete method in my DAO class to return each IEnumerable<*DTO>, and then have my service class be responsible for orchestrating the calls to the DAO. It then returns the fully assembled object graph to the client: public class SomeService(){ public SomeService(IDao someDao){ this._someDao = someDao; } public IEnumerable<CustomerDTO> ListCustomersForHistory(int brokerId){ var customers = _someDao.ListCustomersForBroker(brokerId); foreach (customer in customers){ customer.Addresses = someDao.ListCustomersAddresses(brokerId); customer.LatestOrder = someDao.GetCustomerLatestOrder(brokerId); } } return customers; } My question is should this logic belong in the service layer or the should I make my DAO such that it instead returns the assembled object graph. If I was using NHibernate, I assume that this kind of relationship association between objects comes for "free"?

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• Freestanding ARM C++ Code - empty .ctors section

  - by Matthew Iselin

  I'm writing C++ code to run in a freestanding environment (basically an ARM board). It's been going well except I've run into a stumbling block - global static constructors. To my understanding the .ctors section contains a list of addresses to each static constructor, and my code simply needs to iterate this list and make calls to each function as it goes. However, I've found that this section in my binary is in fact completely empty! Google pointed towards using ".init_array" instead of ".ctors" (an EABI thing), but that has not changed anything. Any ideas as to why my static constructors don't exist? Relevant linker script and objdump output follows: .ctors : { . = ALIGN(4096); start_ctors = .; *(.init_array); *(.ctors); end_ctors = .; } .dtors : { . = ALIGN(4096); start_dtors = .; *(.fini_array); *(.dtors); end_dtors = .; } -- 2 .ctors 00001000 8014c000 8014c000 00054000 2**2 CONTENTS, ALLOC, LOAD, DATA <snip> 8014d000 g O .ctors 00000004 start_ctors <snip> 8014d000 g O .ctors 00000004 end_ctors I'm using an arm-elf targeted GCC compiler (4.4.1).

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• DELETE causing a redirect loop?

  - by robocode

  I have an express app with a postgres backend where a user can add/delete recipes, and each time they do so they get an updated list of recipes. Adding a recipe is fine, but when I delete one it seems to get stuck in a redirect loop. In app.js I have router.get('/delete/:d', delRec.deleteRecipe); which calls the following code exports.deleteRecipe = function(req, res){ pg.connect(conString, function(err, client) { client.query('DELETE FROM recipes WHERE recipe_name = ', [req.params.d], function(err, result) { if(err) { return console.error('error running query', err); } else if (result) { pg.end(); console.log('deleting'); } }); }); res.redirect('recipes'); }; If I try delete a recipe, console.log('deleting') produces deleting deleting deleting deleting deleting deleting deleting deleting deleting deleting deleting deleting deleting deleting deleting deleting deleting deleting deleting deleting deleting The recipes route is below (sorry that it's so convoluted) router.get('/recipes', function(req, res) { pg.connect(conString, function(err, client) { if(err) { return console.error('could not connect to postgres', err); } client.query('SELECT * FROM recipes', function(err, result) { if(err) { return console.error('error running query', err); } recipes = result.rows; for(var d in recipes) { if (recipes.hasOwnProperty(d)) { recipeList[d] = recipes[d].recipe_name; } } res.render('recipes', {recipes: recipes, recipeList: recipeList}); }); }); });

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• [C#]How to introduce retry logic into LINQ to SQL to deal with timeouts?

  - by codemonkie

  I need to find ways to add retry mechanism to my DB calls in case of timeouts, LINQ to SQL is used to call some sprocs in my code... using (MyDataContext dc = new MyDataContext()) { int result = -1; //denote failure int count = 0; while ((result < 0) && (count < MAX_RETRIES)) { result = dc.myStoredProc1(...); count++; } result = -1; count = 0; while ((result < 0) && (count < MAX_RETRIES)) { result = dc.myStoredProc2(...); count++; } ... ... } Not sure if the code above is right or posed any complications. It'll be nice to throw an exception after MAX_RETRIES has reached, but I dunno how and where to throw them appropriately :-) Any helps appreciated.

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• Rescuing a failed WCF call

  - by illdev

  Hello, I am happily using Castle's WcfFacility. From Monorail I know the handy concept of Rescues - consumer friendly results that often, but not necessarily, contain Data about what went wrong. I am creating a Silverlight application right now, doing quite a few WCF service calls. All these request return an implementation of public class ServiceResponse { private string _messageToUser = string.Empty; private ActionResult _result = ActionResult.Success; public ActionResult Result // Success, Failure, Timeout { get { return _result; } set { _result = value; } } public string MessageToUser { get { return _messageToUser; } set { _messageToUser = value; } } } public abstract class ServiceResponse<TResponseData> : ServiceResponse { public TResponseData Data { get; set; } } If the service has trouble responding the right way, I would want the thrown Exception to be intercepted and converted to the expected implementation. base on the thrown exception, I would want to pass on a nice message. here is how one of the service methods looks like: [Transaction(TransactionMode.Requires)] public virtual SaveResponse InsertOrUpdate(WarehouseDto dto) { var w = dto.Id > 0 ? _dao.GetById(dto.Id) : new Warehouse(); w.Name = dto.Name; _dao.SaveOrUpdate(w); return new SaveResponse { Data = new InsertData { Id = w.Id } }; } I need the thrown Exception for the Transaction to be rolled back, so i cannot actually catch it and return something else. Any ideas, where I could hook in?

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• Mocking non-virtual methods in C++ without editing production code?

  - by wk1989

  Hello, I am a fairly new software developer currently working adding unit tests to an existing C++ project that started years ago. Due to a non-technical reason, I'm not allowed to modify any existing code. The base class of all my modules has a bunch of methods for Setting/Getting data and communicating with other modules. Since I just want to unit testing each individual module, I want to be able to use canned values for all my inter-module communication methods. I.e. for a method Ping() which checks if another module is active, I want to have it return true or false based on what kind of test I'm doing. I've been looking into Google Test and Google Mock, and it does support mocking non-virtual methods. However the approach described (http://code.google.com/p/googlemock/wiki/CookBook#Mocking_Nonvirtual_Methods) requires me to "templatize" the original methods to take in either real or mock objects. I can't go and templatize my methods in the base class due to the requirement mentioned earlier, so I need some other way of mocking these virtual methods Basically, the methods I want to mock are in some base class, the modules I want to unit test and create mocks of are derived classes of that base class. There are intermediate modules in between my base Module class and the modules that I want to test. I would appreciate any advise! Thanks, JW EDIT: A more concrete examples My base class is lets say rootModule, the module I want to test is leafModule. There is an intermediate module which inherits from rootModule, leafModule inherits from this intermediate module. In my leafModule, I want to test the doStuff() method, which calls the non virtual GetStatus(moduleName) defined in the rootModule class. I need to somehow make GetStatus() to return a chosen canned value. Mocking is new to me, so is using mock objects even the right approach?

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• ASP .NET Button event handlers do not fire on the first click, but on the second click after a PostB

  - by John

  Background: I am customizing an existing ASP .NET / C# application. It has it's own little "framework" and conventions for developers to follow when extending/customizing its functionality. I am currently extending some of it's administrative functionality, to which the framework provides a contract to enforce implementation of the GetAdministrationInterface() method, which returns System.Web.UI.Control. This method is called during the Page_Load() method of the page hosting the GUI interface. Problem: I have three buttons in my GUI, each of which have been assigned an Event Handler. My administration GUI loads up perfectly fine, but clicking any of the buttons doesn't do what I expect them to do. However, when I click them a second time, the buttons work. I placed breakpoints at the beginning of each event handler method and stepped through my code. On the first click, none of the event handlers were triggered. On the second click, they fired. Any ideas? Example of Button Definition (within GetAdministrationInterface) public override Control GetAdministrationInterface() { // more code... Button btn = new Button(); btn.Text = "Click Me!"; btn.Click += new EventHandler(Btn_Click); // more code... } Example of Event Handler Method Definition void Btn_Click(object sender, EventArgs e) { // Do Something } Page_Load Method that calls GetAdministrationInterface protected void Page_Load(object sender, System.EventArgs e) { if (!Page.IsAsync) { List<AdministrationInterface> interfaces = <DATABASE CALL>; foreach(AdministrationInteface ai in interfaces) { placeholderDiv.Controls.Add(ai.GetAdministrationInterface()); } } }

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• Does breaking chained Select()s in LINQ to objects hurt performance?

  - by Justin

  Take the following pseudo C# code: using System; using System.Data; using System.Linq; using System.Collections.Generic; public IEnumerable<IDataRecord> GetRecords(string sql) { // DB logic goes here } public IEnumerable<IEmployer> Employers() { string sql = "select EmployerID from employer"; var ids = GetRecords(sql).Select(record => (record["EmployerID"] as int?) ?? 0); return ids.Select(employerID => new Employer(employerID) as IEmployer); } Would it be faster if the two Select() calls were combined? Is there an extra iteration in the code above? Is the following code faster? public IEnumerable<IEmployer> Employers() { string sql = "select EmployerID from employer"; return Query.Records(sql).Select(record => new Employer((record["EmployerID"] as int?) ?? 0) as IEmployer); } I think the first example is more readable if there is no difference in performance.

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• C++ Storing variables and inheritance

  - by Kaa

  Hello Everyone, Here is my situation: I have an event driven system, where all my handlers are derived from IHandler class, and implement an onEvent(const Event &event) method. Now, Event is a base class for all events and contains only the enumerated event type. All actual events are derived from it, including the EventKey event, which has 2 fields: (uchar) keyCode and (bool)isDown. Here's the interesting part: I generate an EventKey event using the following syntax: Event evt = EventKey(15, true); and I ship it to the handlers: EventDispatch::sendEvent(evt); // void EventDispatch::sendEvent(const Event &event); (EventDispatch contains a linked list of IHandlers and calls their onEvent(const Event &event) method with the parameter containing the sent event. Now the actual question: Say I want my handlers to poll the events in a queue of type Event, how do I do that? x Dynamic pointers with reference counting sound like too big of a solution. x Making copies is more difficult than it sounds, since I'm only receiving a reference to a base type, therefore each time I would need to check the type of event, upcast to EventKey and then make a copy to store in a queue. Sounds like the only solution - but is unpleasant since I would need to know every single type of event and would have to check that for every event received - sounds like a bad plan. x I could allocate the events dynamically and then send around pointers to those events, enqueue them in the array if wanted - but other than having reference counting - how would I be able to keep track of that memory? Do you know any way to implement a very light reference counter that wouldn't interfere with the user? What do you think would be a good solution to this design? I thank everyone in advance for your time. Sincerely, Kaa

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• XNA: What can cause SpriteBatch.End() to throw a NRE?

  - by Rosarch

  I don't understand what I'm doing wrong here: public void Draw(GameTime gameTime) // in ScreenManager { SpriteBatch.Begin(SpriteBlendMode.AlphaBlend); for (int i = 0; i < Screens.Count; i++) { if (Screens[i].State == Screen.ScreenState.HIDDEN) continue; Screens[i].Draw(gameTime); } SpriteBatch.End(); // null ref exception } SpriteBatch itself is not null. Some more context: public class MasterEngine : Microsoft.Xna.Framework.Game { public MasterEngine() { graphicsDeviceManager = new GraphicsDeviceManager(this); Components.Add(new GamerServicesComponent(this)); // ... spriteBatch = new SpriteBatch(graphicsDeviceManager.GraphicsDevice); screenManager = new ScreenManager(assets, gameEngine, graphicsDeviceManager.GraphicsDevice, spriteBatch); } //... protected override void Draw(GameTime gameTime) { screenManager.Draw(gameTime); // calls the problematic method base.Draw(gameTime); } } Am I failing to initialize something properly? UPDATE: As an experiment, I tried this to the constructor of MasterEngine: spriteBatch = new SpriteBatch(graphicsDeviceManager.GraphicsDevice); spriteBatch.Begin(); spriteBatch.DrawString(assets.GetAsset<SpriteFont>("calibri"), "ftw", new Vector2(), Color.White); spriteBatch.End(); This does not cause a NRE. hmm.... UPDATE 2: This does cause an NRE: protected override void Draw(GameTime gameTime) { spriteBatch.Begin(); spriteBatch.End(); // boned here //screenManager.Draw(gameTime); base.Draw(gameTime); }

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• Codeigniter only loads the default controller

  - by fh47331

  I am very new to CodeIgniter, but have been programming PHP for ages. I'm writing some software at the moment and using CI for the first time with it. The default controller is set to the first controller I want to action call 'login' (the controller is login.php, the view is login.php. When the form is submitted it calls the 'authenticate' controller. This executes fine, process the login data correctly and then does a redirect command (without any output to the screen prior) to the next page in this case 'newspage'. The problem is that the redirect, never reaches 'newspage' but the default controller runs again. It doesn't matter what I put ... ht tp://domain.name/anything ... (yes im using .htaccess to remove the index.php) the anything never gets called, just the default controller. I have left the standard 'welcome.php' controller and 'welcome_message.php' in the folders and even putting ht tp://domain.name/welcome all I get is the login screen! (Obviously there shouldn't be a space between the http - thats just done so it does not show as a hyperlink!) Can anyone tell me what i've done wrong!

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• About calling an subclass' overriding method when casted to its superclass

  - by Omega

  #include <iostream> class Vehicle { public: void greet() { std::cout << "Hello, I'm a vehicle"; } }; class Car : public Vehicle { public: void greet() { std::cout << "Hello, I'm a car"; } }; class Bike : public Vehicle { public: void greet() { std::cout << "Hello, I'm a bike"; } }; void receiveVehicle(Vehicle vehicle) { vehicle.greet(); } int main() { receiveVehicle(Car()); return 0; } As you can see, I'm trying to send a parameter of type Vehicle to a function, which calls greet(). Car and Bike are subclasses of Vehicle. They overwrite greet(). However, I'm getting "Hello, I'm a vehicle". I suppose that this is because receiveVehicle receives a parameter of type Vehicle instead of a specific subclass like Car or Bike. But that's what I want: I want this function to work with any subclass of Vehicle. Why am I not getting the expected output?

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• Apply [ThreadStatic] attribute to a method in external assembly

  - by Sen Jacob

  Can I use an external assembly's static method like [ThreadStatic] method? Here is my situation. The assembly class (which I do not have access to its source) has this structure public class RegistrationManager() { private RegistrationManager() {} public static void RegisterConfiguration(int ID) {} public static object DoWork() {} public static void UnregisterConfiguration(int ID) {} } Once registered, I cannot call the DoWork() with a different ID without unregistering the previously registered one. Actually I want to call the DoWork() method with different IDs simultaneously with multi-threading. If the RegisterConfiguration(int ID) method was [ThreadStatic], I could have call it in different threads without problems with calls, right? So, can I apply the [ThreadStatic] attribute to this method or is there any other way I can call the two static methods same time without waiting for other thread to unregister it? If I check it like the following, it should work. for(int i=0; i < 10; i++) { new Thread(new ThreadStart(() => Checker(i))).Start(); } public string Checker(int i) { public static void RegisterConfiguration(i); // Now i cannot register second time public static object DoWork(i); Thread.Sleep(5000); // DoWork() may take a little while to complete before unregistered public static void UnregisterConfiguration(i); }

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• How to detect whether an EventWaitHandle is waiting?

  - by AngryHacker

  I have a fairly well multi-threaded winforms app that employs the EventWaitHandle in a number of places to synchronize access. So I have code similar to this: List<int> _revTypes; EventWaitHandle _ewh = new EventWaitHandle(false, EventResetMode.ManualReset); void StartBackgroundTask() { _ewh.Reset(); Thread t = new Thread(new ThreadStart(LoadStuff)); t.Start(); } void LoadStuff() { _revTypes = WebServiceCall.GetRevTypes() // ...bunch of other calls fetching data from all over the place // using the same pattern _ewh.Set(); } List<int> RevTypes { get { _ewh.WaitOne(); return _revTypes; } } Then I just call .RevTypes somewehre from the UI and it will return data to me when LoadStuff has finished executing. All this works perfectly correctly, however RevTypes is just one property - there are actually several dozens of these. And one or several of these properties are holding up the UI from loading in a fast manner. Short of placing benchmark code into each property, is there a way to see which property is holding the UI from loading? Is there a way to see whether the EventWaitHandle is forced to actually wait?

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• Compromising design & code quality to integrate with existing modules

  - by filip-fku

  Greetings! I inherited a C#.NET application I have been extending and improving for a while now. Overall it was obviously a rush-job (or whoever wrote it was seemingly less competent than myself). The app pulls some data from an embedded device & displays and manipulates it. At the core is a communications thread in the main application form which executes a 600+ lines of code method which calls functions all over the place, implementing a state machine - lots of if-state-then-do type code. Interaction with the device is done by setting the state/mode globally and letting the thread do it's thing. (This is just one example of the badness of the code - overall it is not very OO-like, it reminds of the style of embedded C code the device firmware is written in). My problem is that this piece of code is central to the application. The software, communications protocol or device firmware are not documented at all. Obviously to carry on with my work I have to interact with this code. What I would like some guidance on, is whether it is worth scrapping this code & trying to piece together something more reasonable from the information I can reverse engineer? I can't decide! The reason I don't want to refactor is because the code already works, and changing it will surely be a long, laborious and unpleasant task. On the flip side, not refactoring means I have to sometimes compromise the design of other modules so that I may call my code from this state machine! I've heard of "If it ain't broke don't fix it!", so I am wondering if it should apply when "it" is influencing the design of future code! Any advice would be appreciated! Thanks!

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• Flex component setActualSize

  - by dlots

  I am a little confused about the setActualSize method. It appears from what I've read, that if it is not called on a component by its parent, the component will not be rendered. So it appears that setActualSize is a critical method that is directly bound to rendering the UIComponent. It also appears that the width and height properties of UIComponent override the functionality of the width and height properties of flash.display.DisplayObject, in that they are not directly bound to the rendering of the object but are virtual values that are mainly used by the getExplicitOrMeasured when the parent of the component calls the component's setActualSize method. So the question are: 1) Why isn't the default behavior of every component to just call setActualSize(getExplicitOrMeasuredWidth(),getExplicitOrMeasuredHeight()) on itself? 2) I guess this question stems from the above question and the behavior as I understand it as described above: does setActualSize change the visibility of the component? It appears that that the behavior is that a component is not rendered until setActualSize is called, but if it contains display object children itself (expected behavior as it can calculate measure on itself) and is added to the display list, the only reason why flash isn't rendering it, is because its not visible. 3) Relating to question #1, does updateDisplayList of UIComponent have a method that goes through its children calling setActualSize on each of them?

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• What makes you trust that a piece of open source software is not malicious?

  - by Daniel DiPaolo

  We developers are in a unique position when it comes to the ability to not only be skeptical about the capabilities provided by open source software, but to actively analyze the code since it is freely available. In fact, one may even argue that open source software developers have a social responsibility to do so to contribute to the community. But at what point do you as a developer say, "I better take a look at what this is doing before I trust using it" for any given thing? Is it a matter of trusting code with your personal information? Does it depend on the source you're getting it from? What spurred this question on was a post on Hacker News to a javascript bookmarklet that supposedly tells you how "exposed" your information on Facebook is as well as recommending some fixes. I thought for a second "I'd rather not start blindly running this code over all my (fairly locked down) Facebook information so let me check it out". The bookmarklet is simple enough, but it calls another javascript function which at the time (but not anymore) was highly compressed and undecipherable. That's when I said "nope, not gonna do it". So even though I could have verified the original uncompressed javascript from the Github site and even saved a local copy to verify and then run without hitting their server, I wasn't going to. It's several thousand lines and I'm not a total javascript guru to begin with. Yet, folks are using it anyway. Even (supposedly) bright developers. What makes them trust the script? Did they all scrutinize it line by line? Do they know the guy personally and trust him not to do anything bad? Do they just take his word? What makes you trust that a piece of open source software is not malicious?

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