Search Results

Search found 7436 results on 298 pages for 'simultaneous calls'.

Page 46/298 | < Previous Page | 42 43 44 45 46 47 48 49 50 51 52 53  | Next Page >

  • Why is there no facility to overload static properties in PHP?

    - by Jon
    Intro PHP allows you to overload method calls and property accesses by declaring magic methods in classes. This enables code such as: class Foo { public function __get($name) { return 42; } } $foo = new Foo; echo $foo->missingProperty; // prints "42" Apart from overloading instance properties and methods, since PHP 5.3.0 we can also overload static methods calls by overriding the magic method __callStatic. Something missing What is conspicuously missing from the available functionality is the ability to overload static properties, for example: echo Foo::$missingProperty; // fatal error: access to undeclared static property This limitation is clearly documented: Property overloading only works in object context. These magic methods will not be triggered in static context. Therefore these methods should not be declared static. As of PHP 5.3.0, a warning is issued if one of the magic overloading methods is declared static. But why? My questions are: Is there a technical reason that this functionality is not currently supported? Or perhaps a (shudder) political reason? Have there been any aborted attempts to add this functionality in the past? Most importantly, the question is not "how can I have dynamic static properties in userland PHP?". That said, if you know of an especially cute implementation based on __callStatic that you want to share then by all means do so.

    Read the article

  • Go/Obj-C style interfaces with ability to extend compiled objects after initial release

    - by Skrylar
    I have a conceptual model for an object system which involves combining Go/Obj-C interfaces/protocols with being able to add virtual methods from any unit, not just the one which defines a class. The idea of this is to allow Ruby-ish open classes so you can take a minimalist approach to library development, and attach on small pieces of functionality as is actually needed by the whole program. Implementation of this involves a table of methods marked virtual in an RTTI table, which system functions are allowed to add to during module initialization. Upon typecasting an object to an interface, a Go-style lookup is done to create a vtable for that particular mapping and pass it off so you can have comparable performance to C/C++. In this case, methods may be added /afterwards/ which were not previously known and these new methods allow newer interfaces to be satisfied; while I like this idea because it seems like it would be very flexible (disregarding the potential for spaghetti code, which can happen with just about any model you use regardless). By wrapping the system calls for binding methods up in a set of clean C-compatible calls, one would also be able to integrate code with shared libraries and retain a decent amount of performance (Go does not do shared linking, and Objective-C does a dynamic lookup on each call.) Is there a valid use-case for this model that would make it worth the extra background plumbing? As much as this Dylan-style extensibility would be nice to have access to, I can't quite bring myself to a use case that would justify the overhead other than "it could make some kinds of code more extensible in future scenarios."

    Read the article

  • Standard Network Tiers in a Distributed N-Tier System

    Distributed N-Tier client/server architecture allows for segments of an application to be broken up and distributed across multiple locations on a network.  Listed below are standard tiers in a Distributed N-Tier System. End-User Client Tier The End-User Client is responsible for sending and receiving requests from web servers and other applications servers and translating the responses so that the End-User can interpret the data effectively. The primary roles for this tier are to communicate with servers and translate server responses back to the end-user to interpret. Business-Specific Functions Validate Data Display Data Send Data to Webserver Web Server Tier The Web server tier processes new requests for information coming in from the HTTP and HTTPS ports. This primarily handles the generation of user interfaces and calls the application server when needed to access Data and business logic when needed. Business-specific functions Send Data to application server Format Data for Display Validate Data Application Server Tier The application server stores and executes predefined business logic that is applied to various pieces of data as the business determines. The processed data is then returned back to the Webserver. Additionally, this server directly calls the database to obtain and store any data used by the system Business-Specific Functions Validate Data Process Data Send Data to Database Server Database Server Tier The Database Server is responsible for storing and returning all data need by the calling applications. The primary role for this this server is storage. Data is stored as needed and can be recalled at any point later in time. Business-Specific Functions Insert Data Delete Data Return Data to Application Server

    Read the article

  • Javascript Canvas Drawing Efficiency

    - by jujumbura
    I have just recently started some experiments with game development in Javascript/HTML5, and so far it has been going pretty well. I have a simple test scene running with some basic input handling, and a hundred-ish drawImage() calls with a few transforms. This all runs great on Chrome, but unfortunately, it already chugs on Firefox. I am using a very large canvas ( 1920 x 1080 ), but it doesn't seem like I should be hitting my limit already. So on that note, I was hoping to ask a few questions: 1) What exactly is done on the CPU vs. the GPU in terms of canvas and drawImage()? I'm afraid the answer is probably "it depends on the browser", but can anybody give me some rules of thumb? I naively imagined that each drawImage call results in a textured quad on the GPU with the canvas effectively being a render target, but I'm wondering if I'm pretty far off base there... 2) I have seen posts here and there with people saying not to use the translate(), rotate(), scale() functions when drawing on the canvas. Am I adding a lot of overhead just by adding a translate() call, as opposed to passing in the x,y to drawImage()? Some people suggest using "transate3d", etc., which are CSS properties, but I'm not sure how to use them within a scene. Can they be used for animated sprites within a single canvas? 3) I have also seen a lot of posts with people mentioning that pre-building canvases and then re-using them is a lot faster than issuing all the individual draw calls again. I am guessing that my background should definitely be pre-built into a canvas, but how far should I take this? Should I maintain an individual canvas for each sprite, to cache all static image data when not animating? Thank you much for your advice!

    Read the article

  • How often is seq used in Haskell production code?

    - by Giorgio
    I have some experience writing small tools in Haskell and I find it very intuitive to use, especially for writing filters (using interact) that process their standard input and pipe it to standard output. Recently I tried to use one such filter on a file that was about 10 times larger than usual and I got a Stack space overflow error. After doing some reading (e.g. here and here) I have identified two guidelines to save stack space (experienced Haskellers, please correct me if I write something that is not correct): Avoid recursive function calls that are not tail-recursive (this is valid for all functional languages that support tail-call optimization). Introduce seq to force early evaluation of sub-expressions so that expressions do not grow to large before they are reduced (this is specific to Haskell, or at least to languages using lazy evaluation). After introducing five or six seq calls in my code my tool runs smoothly again (also on the larger data). However, I find the original code was a bit more readable. Since I am not an experienced Haskell programmer I wanted to ask if introducing seq in this way is a common practice, and how often one will normally see seq in Haskell production code. Or are there any techniques that allow to avoid using seq too often and still use little stack space?

    Read the article

  • Naming a class that processes orders

    - by p.campbell
    I'm in the midst of refactoring a project. I've recently read Clean Code, and want to heed some of the advice within, with particular interest in Single Responsibility Principle (SRP). Currently, there's a class called OrderProcessor in the context of a manufacturing product order system. This class is currently performs the following routine every n minutes: check database for newly submitted + unprocessed orders (via a Data Layer class already, phew!) gather all the details of the orders mark them as in-process iterate through each to: perform some integrity checking call a web service on a 3rd party system to place the order check status return value of the web service for success/fail email somebody if web service returns fail constantly log to a text file on each operation or possible fail point I've started by breaking out this class into new classes like: OrderService - poor name. This is the one that wakes up every n minutes OrderGatherer - calls the DL to get the order from the database OrderIterator (? seems too forced or poorly named) - OrderPlacer - calls web service to place the order EmailSender Logger I'm struggling to find good names for each class, and implementing SRP in a reasonable way. How could this class be separated into new class with discrete responsibilities?

    Read the article

  • What are my choices for server side sandboxed scripting?

    - by alfa64
    I'm building a public website where users share data and scripts to run over some data. The scripts are run serverside in some sort of sandbox without other interaction this cycle: my Perl program reads from a database a User made script, adds the data to be processed into the script ( ie: a JSON document) then calls the interpreter, it returns the response( a JSON document or plain text), i save it to the database with my perl script. The script should be able to have some access to built in functions added to the scripting language by myself, but nothing more. So i've stumbled upon node.js as a javascript interpreter, and and hour or so ago with Google's V8(does v8 makes sense for this kind of thing?). CoffeeScript also came to my mind, since it looks nice and it's still Javascript. I think javascript is widespread enough and more "sandboxeable" since it doesn't have OS calls or anything remotely insecure ( i think ). by the way, i'm writing the system on Perl and Php for the front end. To improve the question: I'm choosing Javascript because i think is secure and simple enough to implement with node.js, but what other alternatives are for achieving this kind of task? Lua? Python? I just can't find information on how to run a sandboxed interpreter in a proper way.

    Read the article

  • Database Driven Web Application, C# Front-End and F# Back-End meaning

    - by user1473053
    Hi I am an intern working with ASP.NET. My current task is to make a website which will incorporate some jquery viewing features. This project seems to me will be primarily dealing with reading data from a database and making graphs out of them. This will require me to make custom queries from whatever the client is looking at. I think it is going to be what this guy calls an Ad Hoc Query tool My plan for this is to make it a database-driven website. So I can utilize the jquery dynamic viewing capabilities. I stumbled upon the functional programming paradigm and found F#. I read that because of it's functional programming paradigm, it makes it a good language to do asynchronous functions. I read about how you can use this with LINQ to SQL and how easy it is to make queries without actually putting the query language in. I understand the concept of the MVC design pattern. But I don't understand what they mean about C# being the front-end and F# being the back-end. Can someone clarify this to me? Also what are your thoughts about doing this project in this way? Any comments and thoughts are greatly appreciated. I feel as if learning F# will be a great learning experience for me. My guess is that the F# back-end is like the part where it controls the calls to the database. F# is possibly the model part of the design pattern. And C# is the controller. So HTML, Javascript and Jquery stuff will be my View design pattern. Clarify please?

    Read the article

  • GLES2.0 3D Android game performance and multi threading the update?

    - by Ofer
    I have profiled my mixed Java\C++ Android game and I got the following result: https://dl.dropbox.com/u/8025882/PompiDev/AndroidProfile.png As you can see, the pink think is a C++ functions that updates the game. It does things like updating the logic but it mostly it generates a "request list" for rendering. The thing is, I generate DrawLists on C++ and then send them to Java to process and draw using GLES2.0. Since then I was able to improve update from 9ms down to about 7ms, but I would like to ask if I would benefit from multi threading the update? As I understand from that diagram is that the function that takes the most time is the one you see it's color on the timeline. So the pink area is taken mostly by update. The other area has MainOpenGL.Handle as it's main contributor(whch is my java function), but since it's not drawn to the top of the diagram I can conclude other things are happening at the same time that use the CPU? Or even GPU stuff that isn't shown in this diagram. I am not sure how the GPU works on this. Does it calculate stuff in parallel to the CPU? Or is it part of the CPU usage as in SoC? I am not sure. Anyway, in case GPU things DO happen in parallel to CPU, then I would guess that if I do this C++ Update in parallel to the thread that makes the OpenGL calls, I might make use of "dead CPU time" due to GPU stalling or maybe have the GPU calls getting processed earlier because it won't have to wait for Update to finish? How do you suggest to improve performance based on that? Thanks.

    Read the article

  • Will new Twitter API 1.1 allow hashtag/tweet/trend queries without any authentication, i.e. for a client that does not use an user's account at all?

    - by P5music
    I see that, even not being logged in Twitter with an account, if I google hashtags or twitter accounts, twitter show them. I think it should be also possible to get those tweets programmatically but I do not know it for sure, so I ask for confirmation here, especially for the future with the new Twitter API resctrictions. I mean, will it be possible to get tweets from hashtags or accounts without logging in an user account, and so not wanting to access the user settings, subscriptions, etc (because I do not need it), thus not having to respect any token limit? I found these API 1.1 faqs, have I to be concerned? Will an application have to request user authorization just to make public API calls? When API v1.1 is released, user authorization (and access tokens) are required for all API 1.1 requests. In the weeks following release, some methods will require only application-based authentication for certain "userless" contexts. Will an application have to request user authorization just to make public API calls? When API v1.1 is released, user authorization (and access tokens) are required for all API 1.1 requests. In the weeks following release, some methods will require only application-based authentication for certain "userless" contexts. Will the Search API require authentication? The Search API is now part of the official REST API in version 1.1. In addition to serving results in a format consistent with other Tweet resources, usage will also require authentication.

    Read the article

  • .htaccess rules to rewrite URLs to front end page?

    - by Dizzley
    I am adding a new application to my site at example.com/app. I want views at that URL to always open myapp.php. E.g. example.com/app -> example.com/app/myapp.php and example.com/app/ -> example.com/app/myapp.php What's the correct form of rewrite rules in the .htaccess file? I've got: <IfModule mod_rewrite.c> RewriteEngine On RewriteBase /app/ RewriteRule ^myapp\.php$ - [L] RewriteRule ^myapp.php$ - [L] RewriteRule . - [L] </IfModule> ...based on what the Wordpress front-end does. But all I see at example.com/app is a directory of files. :( (I put those rewrites at the top of my .htaccess file). Any ideas? Update What actually worked: RewriteEngine On RewriteBase / RewriteCond %{REQUEST_URI} ^/app(/.*)?$ [NC] RewriteCond %{REQUEST_FILENAME} !-f RewriteRule . /app/myapp.php [L] This is good because: Explicit or implicit calls to app/myapp.php work. example.com/app redirects to app/myapp.php example.com/app/ redirects to app/myapp.php example.com/app/subfunction redirects to app/myapp.php All other calls to example.com/otherstuff are untouched. Item 4 is Wordpress-like Front Controller pattern behaviour. I think that rule RewriteCond %{REQUEST_URI} ^/app.*$ [NC] needs refining as it allows /app-oh-my-goodness etc. through too. Thanks for the answers.

    Read the article

  • The balance between client and server functionality

    - by Eugen Martynov
    I want to bring the discussion that started in our teams and get your opinion about it. Assume we have an user account which could have different credentials for authentication and associated email to recover. An user has possibility to do signup with an email or use his social profile to complete signup process. As an Rest API from the backend to client looks like: Create account Authorise Update user data Link social account Register email Verify email In addition our BE is distributed and divided between several services/servers/clusters. So different calls are related to different end points. In case of the social sign up some of steps should be skipped or simplified. For example, with Facebook signup we could already skip email registration and verification step (we ask email permission form user), linking the social account and pre-fill user displayed name. So we proposed to have another end point which will hide/combine different calls on BE and return whole process result to the clients. The pros for this approach: No more duplication of functionality between clients Speed up the networking and user experience The cons for this approach: Additional work for backend Probably most complex scenarios in future updates I would like to get your opinion or experience with this situation. Especially if you already experienced point #2 from against reasons.

    Read the article

  • Gathering IP address and workstation information; does it belong in a state class?

    - by p.campbell
    I'm writing an enterprisey utility that collects exception information and writes to the Windows Event Log, sends an email, etc. This utility class will be used by all applications in the corporation: web, BizTalk, Windows Services, etc. Currently this class: holds state given to it via public properties calls out to .NET Framework methods to gather information about runtime details. Included are call to various properties and methods from System.Environment, Reflection details, etc. This implementation has the benefit of allowing all those callers not to have to make these same calls themselves. This means less code for the caller to forget, screw up, etc. Should this state class (please what's the phrase I'm looking for [like DTO]?) know how to resolve/determine runtime details (like the IP address and machine name that it's running on)? It seems to me on second thought that it's meant to be a class that should hold state, and not know how to call out to the .NET Framework to find information. var myEx = new AppProblem{MachineName="Riker"}; //Will get "Riker 10.0.0.1" from property MachineLongDesc Console.WriteLine("full machine details: " + myEx.MachineLongDesc); public class AppProblem { public string MachineName{get;set;} public string MachineLongDesc{ get{ if(string.IsNullOrEmpty(this.MachineName) { this.MachineName = Environment.MachineName; } return this.MachineName + " " + GetCurrentIP(); } } private string GetCurrentIP() { return System.Net.Dns.GetHostEntry(this.MachineName) .AddressList.First().ToString(); } } This code was written by hand from memory, and presented for simplicity, trying to illustrate the concept.

    Read the article

  • Is my client correct that I cannot take a vacation as a subcontractor? [closed]

    - by Rae Ann
    I have 2 clients who I do ongoing work for as a subcontractor. Both are sporadic and part-time. Company A sent me to a 3 day certification course out of state. The following week I was scheduled for a 3 day vacation. I warned company B three weeks prior to these events. During my training that Company A was paying for, Company B asked me to leave the training to workon something for them that needed immediate attention. I declined. However I made arrangements to work on it in the evening and in the early mornings after they threatened to take the work and all subsequent work for this client to someone else. I lost all networking and fun from that trip... The following week I was in Florida and was again asked to do more work on the project after the feedback from the client. The integrated product personnel would not cooperate/return any of our calls so I did the best I could. I turned in the work, explained the issue and then was gone for 3 hours. When I returned, all my access to the project had been revoked and after a week of my calls and emails I found out they replaced me. I sent an invoice 3 weeks ago and they tell me they owe me nothing because I did not do the whole project and they cannot bill the client for what I did, because they are billing for the second contractor who started over. I was told that they realize I was on vacation but as a subcontractor I lose the ability to just disappear. I was gone 3 hours! Is this normal, correct, legal?? Not only did they ruin my class and my vacation, but now they expect me to not demand payment? They ended our relationship and I was in the middle of another project of theirs too. They told me to immediately cease all work for them. How do I get paid for the work I have yet to invoice this month?

    Read the article

  • CSOM (Client Side Object Model) - What's new with SharePoint 2013

    - by KunaalKapoor
    SharePoint CSOMThe Client-Side Object Model or CSOM came out with SharePoint 2010. CSOM is accessible through client.svc but all client.svc calls must go through supported WFC entry points (supported entry points are .NET, Silverlight and JavaScript). So a developer would need to use client side proxy objects exposed by either a .NET assembly or a JavaScript library. Changes with SharePoint 2013REST Capabilities - Direct access to client.svcNew APIs - App ModelREST CapabilitiesOne of the most important changes to the CSOM with SharePoint 2013 is that the web service entry point of client.svc has been extended to allow direct access  via REST-Based web service calls. This is a really critical change since its going to make the SharePoint platform accessible to any other platform, opening the horizons of integration and collaboration with other REST based platforms and devices. OData (a really popular standard data access API for HTTP-based clients) is supported similar to 2010 but will be a more important aspect of SharePoint 2013 development.New API'sCSOM for SharePoint 2013 has been buffed up with several new APIs for not only SharePoint server functionality but also an API for Windows Phone applications. For a SharePoint 2010 farm most of the new APIs mentioned below are available only via server side APIs:SearchTaxonomyPublishingWorkflowUser ProfilesE-DiscoveryAnalyticsBusiness DataIRMFeedsSharePoint 2013 remote APIs being accessible through both CSOM and REST is very important to the new app model where developers can no longer run code in a SharePoint environment nor can they access the server-side APIs. So CSOM plays the savior here.Also, you can now substitute the alias '_api' in order to reference '_vti_bin/client.svc'.

    Read the article

  • Design in "mixed" languages: object oriented design or functional programming?

    - by dema80
    In the past few years, the languages I like to use are becoming more and more "functional". I now use languages that are a sort of "hybrid": C#, F#, Scala. I like to design my application using classes that correspond to the domain objects, and use functional features where this makes coding easier, more coincise and safer (especially when operating on collections or when passing functions). However the two worlds "clash" when coming to design patterns. The specific example I faced recently is the Observer pattern. I want a producer to notify some other code (the "consumers/observers", say a DB storage, a logger, and so on) when an item is created or changed. I initially did it "functionally" like this: producer.foo(item => { updateItemInDb(item); insertLog(item) }) // calls the function passed as argument as an item is processed But I'm now wondering if I should use a more "OO" approach: interface IItemObserver { onNotify(Item) } class DBObserver : IItemObserver ... class LogObserver: IItemObserver ... producer.addObserver(new DBObserver) producer.addObserver(new LogObserver) producer.foo() //calls observer in a loop Which are the pro and con of the two approach? I once heard a FP guru say that design patterns are there only because of the limitations of the language, and that's why there are so few in functional languages. Maybe this could be an example of it? EDIT: In my particular scenario I don't need it, but.. how would you implement removal and addition of "observers" in the functional way? (I.e. how would you implement all the functionalities in the pattern?) Just passing a new function, for example?

    Read the article

  • Using ConcurrentQueue for thread-safe Performance Bookkeeping.

    - by Strenium
    Just a small tidbit that's sprung up today. I had to book-keep and emit diagnostics for the average thread performance in a highly-threaded code over a period of last X number of calls and no more. Need of the day: a thread-safe, self-managing stats container. Since .NET 4.0 introduced new thread-safe 'Collections.Concurrent' objects and I've been using them frequently - the one in particular seemed like a good fit for storing each threads' performance data - ConcurrentQueue. But I wanted to store only the most recent X# of calls and since the ConcurrentQueue currently does not support size constraint I had to come up with my own generic version which attempts to restrict usage to numeric types only: unfortunately there is no IArithmetic-like interface which constrains to only numeric types – so the constraints here here aren't as elegant as they could be. (Note the use of the Average() method, of course you can use others as well as make your own).   FIFO FixedSizedConcurrentQueue using System;using System.Collections.Concurrent;using System.Linq; namespace xxxxx.Data.Infrastructure{    [Serializable]    public class FixedSizedConcurrentQueue<T> where T : struct, IConvertible, IComparable<T>    {        private FixedSizedConcurrentQueue() { }         public FixedSizedConcurrentQueue(ConcurrentQueue<T> queue)        {            _queue = queue;        }         ConcurrentQueue<T> _queue = new ConcurrentQueue<T>();         public int Size { get { return _queue.Count; } }        public double Average { get { return _queue.Average(arg => Convert.ToInt32(arg)); } }         public int Limit { get; set; }        public void Enqueue(T obj)        {            _queue.Enqueue(obj);            lock (this)            {                T @out;                while (_queue.Count > Limit) _queue.TryDequeue(out @out);            }        }    } }   The usage case is straight-forward, in this case I’m using a FIFO queue of maximum size of 200 to store doubles to which I simply Enqueue() the calculated rates: Usage var RateQueue = new FixedSizedConcurrentQueue<double>(new ConcurrentQueue<double>()) { Limit = 200 }; /* greater size == longer history */   That’s about it. Happy coding!

    Read the article

  • Rendering multiple squares fast?

    - by Sam
    so I'm doing my first steps with openGL development on android and I'm kinda stuck at some serious performance issues... What I'm trying to do is render a whole grid of single colored squares on to the screen and I'm getting framerates of ~7FPS. The squares are 9px in size right now with one pixel border in between, so I get a few thousand of them. I have a class "Square" and the Renderer iterates over all Squares every frame and calls the draw() method of each (just the iteration is fast enough, with no openGL code the whole thing runs smootlhy at 60FPS). Right now the draw() method looks like this: // Prepare the square coordinate data GLES20.glVertexAttribPointer(mPositionHandle, COORDS_PER_VERTEX, GLES20.GL_FLOAT, false, vertexStride, vertexBuffer); // Set color for drawing the square GLES20.glUniform4fv(mColorHandle, 1, color, 0); // Draw the square GLES20.glDrawElements(GLES20.GL_TRIANGLES, drawOrder.length, GLES20.GL_UNSIGNED_SHORT, drawListBuffer); So its actually only 3 openGL calls. Everything else (loading shaders, filling buffers, getting appropriate handles, etc.) is done in the Constructor and things like the Program and the handles are also static attributes. What am I missing here, why is it rendering so slow? I've also tried loading the buffer data into VBOs, but this is actually slower... Maybe I did something wrong though. Any help greatly appreciated! :)

    Read the article

  • Making efficeint voxel engines using "chunks"

    - by Wardy
    Concept I'm currently looking in to how voxel engines work with a view to possibly making one myself. I see a lot of stuff like this ... https://sites.google.com/site/letsmakeavoxelengine/home/chunks ... which talks about how to go about reducing the draw calls. What I can't seem to understand is how it actually saves draw call counts on the basis of the logic being something like this ... Without chunks foreach voxel in myvoxels DrawIfVisible() With Chunks foreach chunk in mychunks DrawIfVisible() which then does ... foreach voxel in myvoxels DrawIfVisible() So surely you saved nothing ?!?! You still make a draw call for each visible voxel do you not? A visible voxel needs a draw call in either scenario. The only real saving I can see is that the logic that evaluates a chunk will be able to determine if a large number of voxels are visible or not effectively saving a bit of "is this chunk visible" cpu time. But it's the draw calls that interest me ... The fewer of those, the faster the application. EDIT: In case it makes any difference I will probably be using XNA (DX not OpenGL) for my engine so don't consider my choice of example in the link above my choice of technology. But this question is such that I doubt it would matter.

    Read the article

  • How do you plan your asynchronous code?

    - by NullOrEmpty
    I created a library that is a invoker for a web service somewhere else. The library exposes asynchronous methods, since web service calls are a good candidate for that matter. At the beginning everything was just fine, I had methods with easy to understand operations in a CRUD fashion, since the library is a kind of repository. But then business logic started to become complex, and some of the procedures involves the chaining of many of these asynchronous operations, sometimes with different paths depending on the result value, etc.. etc.. Suddenly, everything is very messy, to stop the execution in a break point it is not very helpful, to find out what is going on or where in the process timeline have you stopped become a pain... Development becomes less quick, less agile, and to catch those bugs that happens once in a 1000 times becomes a hell. From the technical point, a repository that exposes asynchronous methods looked like a good idea, because some persistence layers could have delays, and you can use the async approach to do the most of your hardware. But from the functional point of view, things became very complex, and considering those procedures where a dozen of different calls were needed... I don't know the real value of the improvement. After read about TPL for a while, it looked like a good idea for managing tasks, but in the moment you have to combine them and start to reuse existing functionality, things become very messy. I have had a good experience using it for very concrete scenarios, but bad experience using them broadly. How do you work asynchronously? Do you use it always? Or just for long running processes? Thanks.

    Read the article

  • strlen returns incorrect value when called in gdb

    - by alesplin
    So I'm noticing some severely incorrect behavior from calls to standard library functions inside GDB. I have the following program to illustrate: #include <stdio.h> #include <stdlib.h> #include <string.h> int main(int argc, char *argv[]) { char *s1 = "test"; char *s2 = calloc(strlen("test")+1,sizeof(char)); snprintf(s2,strlen("test")+1,"test"); printf("string constant: %lu\n", strlen(s1)); printf("allocated string: %lu\n", strlen(s2)); free(s2); return 0; } When run from the command-line, this program outputs just what you'd expect: string constant: 4 allocated string: 4 However, in GDB, I get the following, incorrect output from calls to strlen(): (gdb) p strlen(s1) $1 = -938856896 (gdb) p strlen(s2) $2 = -938856896 I'm pretty sure this is a problem with glibc shipped with Ubuntu (I'm using 10.10), but this is a serious problem for those of us who spend lots of time in GDB. Is anyone else experiencing this kind of error? What's the best way to fix it? Build glibc from source? (I'm already running a version of GDB built from source)

    Read the article

  • Naming the implementation version of an interface function

    - by bolov
    When I need to write an implementation version of an interface function, I put the implementation function within a impl namespace, but with the same name as the interface function. Is this a bad practice? (the same name part, the namespace part I am confident it’s more than OK). For me, who I write the code, there is no confusion between the two, but I want to make sure this isn’t confusing for someone else. One other option would be to append impl suffix to the function name, but since it is already in a separate namespace named impl it seems redundant. Is there an idiomatic way to do this? E.g.: namespace n { namespace impl { // implementation function (hidden from users) // same name, is it ok? void foo() { // ... //sometimes it needs to call recursively or to call overloads of the interface version: foo(); // calls the implementation version. Is this confusing? n::foo(); // calls the interface version. Is this confusing? // ... } // namespace impl // interface function (exposed to users) void foo() { impl::foo(); } } // namespace n

    Read the article

  • In Ruby, how to I read memory values from an external process?

    - by grg-n-sox
    So all I simply want to do is make a Ruby program that reads some values from known memory address in another process's virtual memory. Through my research and basic knowledge of hex editing a running process's x86 assembly in memory, I have found the base address and offsets for the values in memory I want. I do not want to change them; I just want to read them. I asked a developer of a memory editor how to approach this abstract of language and assuming a Windows platform. He told me the Win32API calls for OpenProcess, CreateProcess, ReadProcessMemory, and WriteProcessMemory were the way to go using either C or C++. I think that the way to go would be just using the Win32API class and mapping two instances of it; One for either OpenProcess or CreateProcess, depending on if the user already has th process running or not, and another instance will be mapped to ReadProcessMemory. I probably still need to find the function for getting the list of running processes so I know which running process is the one I want if it is running already. This would take some work to put all together, but I am figuring it wouldn't be too bad to code up. It is just a new area of programming for me since I have never worked this low level from a high level language (well, higher level than C anyways). I am just wondering of the ways to approach this. I could just use a bunch or Win32API calls, but that means having to deal with a bunch of string and array pack and unpacking that is system dependant I want to eventually make this work cross-platform since the process I am reading from is produced from an executable that has multiple platform builds, (I know the memory address changes from system to system. The idea is to have a flat file that contains all memory mappings so the Ruby program can just match the current platform environment to the matching memory mapping.) but from the looks of things I'll just have to make a class that wraps whatever is the current platform's system shared library memory related function calls. For all I know, there could already exist a Ruby gem that takes care of all of this for me that I am just not finding. I could also possibly try editing the executables for each build to make it so whenever the memory values I want to read from are written to by the process, it also writes a copy of the new value to a space in shared memory that I somehow have Ruby make an instance of a class that is a pointer under the hood to that shared memory address and somehow signal to the Ruby program that the value was updated and should be reloaded. Basically a interrupt based system would be nice, but since the purpose of reading these values is just to send to a scoreboard broadcasted from a central server, I could just stick to a polling based system that sends updates at fixed time intervals. I also could just abandon Ruby altogether and go for C or C++ but I do not know those nearly as well. I actually know more x86 than C++ and I only know C as far as system independent ANSI C and have never dealt with shared system libraries before. So is there a gem or lesser known module available that has already done this? If not, then any additional information as to how to accomplish this would be nice. I guess, long story short, how do I do all this? Thanks in advance, Grg PS: Also a confirmation that those Win32API calls should be aimed at the kernel32.dll library would be nice.

    Read the article

  • WPF BackgroundWorker Execution

    - by Sanju
    Hi All, I've been programming C# for a while now (I'm a Computer Science major), and have never had to implement threading. I am currently building an application for a client that requires threading for a series of operations. Due to the nature of the client/provider agreement, I cannot release the source I am working with. The code that I have posted is in a general form. Pretty much the basic idea of what I am implementing, excluding the content specific source. The first Snippet demonstrates my basic structure, The Progress class is a custom progress window that is displayed as a dialog to prevent user UI interaction. I am currently using the code to complete database calls based on a collection of objects in another area of the application code. For example, I have a collection of "Objects" of one of my custom classes, that I perform these database calls on or on behalf of. My current set up works just fine when I call the "GeneralizedFunction" one and only one time. What I need to do is call this function once for every object in the collection. I was attempting to use a foreach loop to iterate through the collection, then I tried a for loop. For both loops, the result was the same. The Async operation performs exactly as desired for the first item in the collection. This, however, is the only one it works for. For each subsequent item, the progress box (my custom window) displays and immediately closes. In terms of the database calls, the calls for the first item in the collection are the only ones that successfully complete. All others aren't attempted. I've tried everything that I know and don't know to do, but I just cannot seem to get it to work. How can I get this to work for my entire collection? Any and all help is very greatly appreciated. Progress progress; BackgroundWorker worker; // Cancel the current process private void CancelProcess(object sender, EventArgs e) { worker.CancelAsync(); } // The main process ... "Generalized" private void GeneralizedFunction() { progress = new Progress(); progress.Cancel += CancelProcess; progress.Owner = this; Dispatcher pDispatcher = progress.Dispatcher; worker = new BackgroundWorker(); worker.WorkerSupportsCancellation = true; object[] workArgs = { arg1, arg2, arg3}; worker.DoWork += delegate(object s, DoWorkEventArgs args) { /* All main logic here */ foreach(Class ClassObject in ClassObjectCollection) { //Some more logic here UpdateProgressDelegate update = new UpdateProgressDelegate(updateProgress); pDispatcher.BeginInvoke(update, arg1,arg2,arg3); Thread.Sleep(1000); } }; worker.RunWorkerCompleted += delegate(object s, RunWorkerCompletedEventArgs args) { progress.Close(); }; worker.RunWorkerAsync(workArgs); progress.ShowDialog(); } public delegate void UpdateProgressDelegate(arg1,arg2,arg3); private void updateProgress(arg1,arg2,arg3) { //Update progress }

    Read the article

  • Reversing a number in c++

    - by Marcel Bujnowski
    I created a program to show the sum and show the reversed number a person has typed. The sum function works but the revers function is not. Can anyone give me any tips on how to fix it. I created a program to show the sum and show the reversed number a person has typed. The sum function works but the revers function is not. Can anyone give me any tips on how to fix it. #include<iostream> #include<iomanip> using namespace std; void printSum(int n, bool reverse); int sm(int n); int reverseInt(int n); void printAddTable(int n); int main() { int reverse; int sum=0; int n; cout<<"Enter N value:"<<endl; cin>>n; if(n>0) { reverse = true; printSum( n, reverse); // calls the printSum Method } else { //cout<<"enter positive Number only:"<<endl; } sum = sm(n); //err // calls the sum Method reverse = reverseInt(n); // calls the reverseInt Method cout<<"The reverse value is:"<<reverse; printAddTable(n); // calls the printAddTable Method //getch() } //end of main() void printSum(int n, bool reverse) { int sum=0; // print sum of reverse numbers for(int i=n; i>=1; i--) { sum=sum+i; cout<<i<< " "<<"+"<<" "; } cout<<sum; } int sm(int n) {int sum =0; for(int i=1; i<=n; i++) { sum = sum + i ; cout << endl; cout<<i<<" "<<"+"<<" "<<endl; // print n positive integers cout << endl; } cout<< "Are " <<n<< " positive integers"<<endl; cout<< "Sum is "<<sum <<endl; return sum; } int reverseInt(int n) { int reminder=0; int sum =0; while(n<=0) { reminder = n/10; sum = (sum * 10) + reminder; // it returns the reverse number n = n % 10; } return sum; } void printAddTable(int n) { for(int i=1; i<=n; i++) { cout<<i<<endl; for(int j=1; j<=n; j++) // print n X n add table { cout<<i+j<<endl; } } } {

    Read the article

< Previous Page | 42 43 44 45 46 47 48 49 50 51 52 53  | Next Page >