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  • Rails : fighting long http response times with ajax. Is it a good idea? Please, help with implementa

    - by baranov
    Hi, everybody! I've googled some tutorials, browsed some SO answers, and was unable to find a recipe for my problem. I'm writing a web site which is supposed to display almost realtime stock chart. Data is stored in constantly updating MySQL database, I wrote a find_by_sql query code which fetches all the data I need to get my chart drawn. Everything is ok, except performance - it takes from one second to one minute for different queries to fetch all the data from the database, this time includes necessary (My)SQL-server side calculations. This is simply unacceptable. I got the following idea: if the data is queried from the MySQL server one point a time instead of entire dataset, it takes only about 1-100ms to get an individual point. I imagine the data fetch process might be browser-driven. After the user presses the button in order to get a chart drawn, controller makes one request to the database and renders, say, a progress bar, say 1% ready. When the browser gets the response, it immediately makes an (ajax) request, and the server fetches the next piece of data and renders "2%". And so on, until all the data is ready and the server displays the requested chart. Could this be implemented in rails+js, is there a tutorial for solving a similar problem on the Web? I suppose if the thing is feasible at all, somebody should have already done this before. I have read several articles about ajax, I believe I do understand general principles, but never did nontrivial ajax programming myself. Thanks for your time!

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  • Need help choosing database server

    - by The Pretender
    Good day everyone. Recently I was given a task to develop an application to automate some aspects of stocks trading. While working on initial architecture, the database dilemma emerged. What I need is a fast database engine which can process huge amounts of data coming in very fast. I'm fairly experienced in general programming, but I never faced a task of developing a high-load database architecture. I developed a simple MSSQL database schema with several many-to-many relationships during one of my projects, but that's it. What I'm looking for is some advice on choosing the most suitable database engine and some pointers to various manuals or books which describe high-load database development. Specifics of the project are as follows: OS: Windows NT family (Server 2008 / 7) Primary platform: .NET with C# Database structure: one table to hold primary items and two or three tables with foreign keys to the first table to hold additional information. Database SELECT requirements: Need super-fast selection by foreign keys and by combination of foreign key and one of the columns (presumably DATETIME) Database INSERT requirements: The faster the better :) If there'll be significant performance gain, some parts can be written in C++ with managed interfaces to the rest of the system. So once again: given all that stuff I just typed, please give me some advice on what the best database for my project is. Links or references to some manuals and books on the subject are also greatly appreciated. EDIT: I'll need to insert 3-5 rows in 2 tables approximately once in 30-50 milliseconds and I'll need to do SELECT with 0-2 WHERE clauses queries with similar rate.

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  • Why isn't my new object being seen? C#

    - by Dan
    I am getting ready to take a class at a college on C#. I have been reading up on it a lot and decided to start a fun project. Here is what my project consists of: Main Control Form Configuration Form Arduino Program.cs calls Configuration.cs at start. This is where pin modes for the Arduino are set and where a timer is set. When I set these values, they get sent to MainControl.cs. When I hit the "Save" button in Configuration.cs, a MainControl.cs object is created [[I am correct in that?]] All of those values that were sent by Configuration.cs had corresponding setters that set private static variables in MainControl.cs [[ I don't really know if that is the preferred way, I am most definetly open to any suggestion anyone has]] MainControl.cs uses its default constructor, and this constructor calls a method that creates an arduino object from one of the private variables (serialPort) [[ Using this Arduino class Firmata.NET ]] When the arduino object is created, I know (I guess I do) because the form takes a few seconds to come up (As opposed to not using serial port) My problem is this: I do not understand why nothing can see the object I have been very wordy, I apologize if I wasn't concise. Here is the code: public partial class CMainControl : Form { private static string serialPort; public CMainControl() { InitializeComponent(); createArduino(); updateConfig(); // Change label values to values set in configuration } private void createArduino() { Arduino arduino = new Arduino(serialPort); } In Configuration.cs, when I set the serial port through a combobox, the value is sent to MainControl.cs just fine. Here is the error I get: Error 1 The name 'arduino' does not exist in the current context C:\Programming\Visual Studio\Workhead Demo\Workhead Demo\CMainControl.cs 94 13 Workhead Demo Please let me know if anyone can help and/or offer pointers, and please let me know if I didn't post or format anything correctly. Thank you very much :)

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  • Porting an IBXpress Interbase 6 app to the current Firebird platform, on Delphi 7?

    - by robsoft
    Just wondering if there are any gotchas to be wary of here. We have a legacy D7 app that we developed several years ago for a client, which uses IBXpress to talk to the open source Interbase 6 build. We're having a number of issues with that platform these days (very slow to connect/start-up on new hardware being the chief one) and the client has okayed spending some time/money moving the database over to Firebird. We really DON'T want to embark upon moving it to D2010 (or D2007 which would be my preference right now) as we figure that we might have to move the database layer from IBXpress to something else to best suit Firebird anyway. And at the end of the day, the client is only looking to lessen the database pain, not overhaul/upgrade/rewrite the app. Given the ancestry of Firebird, is it a fairly painless, well-understood path from IBXpress Interbase 6 to (whatever) with Firebird? We have quite a number of sprocs, triggers (and even datatypes) etc in the existing IB database already (and the client has a number of paying customers all using this platform) so we felt that going to Firebird was more likely to be a smoother move than moving to SQL Express (or another flavour of DB entirely). Note that we're not looking for 'embedded' DB advocacy - in many of our client's customers' installations, the software is used in a multi-user client-server way so keeping that kind of approach is important.

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  • Which languages support *recursive* function literals / anonymous functions?

    - by Hugh Allen
    It seems quite a few mainstream languages support function literals these days. They are also called anonymous functions, but I don't care if they have a name. The important thing is that a function literal is an expression which yields a function which hasn't already been defined elsewhere, so for example in C, &printf doesn't count. EDIT to add: if you have a genuine function literal expression <exp>, you should be able to pass it to a function f(<exp>) or immediately apply it to an argument, ie. <exp>(5). I'm curious which languages let you write function literals which are recursive. Wikipedia's "anonymous recursion" article doesn't give any programming examples. Let's use the recursive factorial function as the example. Here are the ones I know: JavaScript / ECMAScript can do it with callee: function(n){if (n<2) {return 1;} else {return n * arguments.callee(n-1);}} it's easy in languages with letrec, eg Haskell (which calls it let): let fac x = if x<2 then 1 else fac (x-1) * x in fac and there are equivalents in Lisp and Scheme. Note that the binding of fac is local to the expression, so the whole expression is in fact an anonymous function. Are there any others?

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  • Why can't I create a database in an empty ASP MVC 2 project using Project->Add->New Item->SQL Server

    - by Dr Dork
    I'm diving head first into ASP MVC and am playing around with creating and manipulating a database. I did a search and found this tutorial for creating a database, however when I follow it, I get this error when trying to add a new database to my fresh, empty ASP MVC 2 project... A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: SQL Network Interfaces, error: 26 - Error Locating Server/Instance Specified) The only requirement the tutorial mentioned was SQL Server Express, but when I went to download it, it said it was already installed. I'm assuming it was part of the VS 2010 RC I installed and am running. So I don't know what else I need if I am missing something. This is all new to me, so I'm sure I'm missing something obvious here and after I'm done posting this question, I plan to do some more research into the topic of databases and how they work with ASP MVC. In the meantime, I was you could help me answer a couple high level questions... What am I missing/forgetting to do that is causing this error? Any suggestions for good resources/tutorials that focus on using databases with ASP MVC? I've done a lot of database programming in the past, so I'm familiar with the concepts of relational databases and the SQL language. I wish I could find a good resource for learning how to work with them in an ASP dev environment, as well as a good breakdown of all the related technologies used for working with them (i.e. LINQ to SQL). Thanks so much in advance for all your help! I'm going to start researching these questions right now.

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  • Why do people say that Ruby is slow?

    - by stephen murdoch
    I like Ruby on Rails and I use it for all my web development projects. A few years ago there was a lot of talk about Rails being a memory hog and about how it didn't scale very well but these suggestions were put to bed by Gregg Pollack here. Lately though, I've been hearing people saying that Ruby itself is slow. Why is Ruby considered slow? I do not find Ruby to be slow but then again, I'm just using it to make simple CRUD apps and company blogs. What sort of projects would I need to be doing before I find Ruby becoming slow? Or is this slowness just something that affects all programming languages? What are your options as a Ruby programmer if you want to deal with this "slowness"? Which version of Ruby would best suit an application like Stack Overflow where speed is critical and traffic is intense? The questions are subjective, and I realise that architectural setup (EC2 vs standalone servers etc) makes a big difference but I'd like to hear what people think about Ruby being slow. Finally, I can't find much news on Ruby 2.0 - I take it we're a good few years away from that then?

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  • PIC C - USB_CDC_GETC() and retrieving strings.

    - by Adam
    Hi all, I'm programming a PIC18F4455 Microcontroller using PIC C. I'm using the USB_CDC.h header file. I have a program on the computer sending a string such as "W250025". However, when I use usb_cdc_getc() to get the first char, it freezes. Sometimes the program sends only 'T', so I really want to just get the first character. Why does my code never execute past received=usb_cdc_getc(); when I send "W250025"? if (usb_cdc_kbhit()) { //printf(lcd_putc, "Check 3"); delay_ms(3000); printf(lcd_putc, "\f"); received = usb_cdc_getc(); printf(lcd_putc, "Received "); lcd_putc(received); delay_ms(3000); printf(lcd_putc, "\f"); if (received == 'W'){ //waveform disable_interrupts(INT_TIMER1); set_adc_channel(0); load_and_print_array(read_into_int(), read_into_int());} else if (received == 'T'){ //temperature set_adc_channel(1); enable_interrupts(INT_TIMER1);} }

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  • jQuery .load() and sub-pages

    - by user354051
    Hi, I am not just a newbie with Javascript. I am developing a simple site to get my hands on web programming. The web site is simple and structure is like this: A simple ul/li/css based navigation menu Sub pages are loaded in "div" using jQuery, when ever user click appropriate menu item. Some of the sub-pages are using different jQuery based plugins such as LightWindow, jTip etc. The jQuery function that loads the sub-page is like this: function loadContent(htmlfile){ jQuery("#content").load(htmlfile); }; The menu items fires loadContent method like this: <li><a href="javascript:void(0)" onclick="loadContent('overview.html');return false">overview</a></li> This loads a sub-page name "overview.html" inside the "div". That's it. Now this is working fine but some of the sub-pages using jQuery based plugins are not working well when loaded inside the "div". If you load them individually in the browser they are working fine. Based on above I have few qustions: Most of the plugins are based on jQuery and sub-pages are loaded inside the "index.html" using "loadContent" function. Do I have to call <script type="text/javascript" src="js/jquery-1.4.2.min.js"></script> on each and every sub-page? If a page is using a custom jQuery plugin, then where do I call it? In "index.html" or on the page where I am using it? I think what ever script you will call in "index.html", you don't to have call them again in any of the sub pages you are using. Am I right here? Thanks Prashant

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  • Can you force a crash if a write occurs to a given memory location with finer than page granularity?

    - by Joseph Garvin
    I'm writing a program that for performance reasons uses shared memory (alternatives have been evaluated, and they are not fast enough for my task, so suggestions to not use it will be downvoted). In the shared memory region I am writing many structs of a fixed size. There is one program responsible for writing the structs into shared memory, and many clients that read from it. However, there is one member of each struct that clients need to write to (a reference count, which they will update atomically). All of the other members should be read only to the clients. Because clients need to change that one member, they can't map the shared memory region as read only. But they shouldn't be tinkering with the other members either, and since these programs are written in C++, memory corruption is possible. Ideally, it should be as difficult as possible for one client to crash another. I'm only worried about buggy clients, not malicious ones, so imperfect solutions are allowed. I can try to stop clients from overwriting by declaring the members in the header they use as const, but that won't prevent memory corruption (buffer overflows, bad casts, etc.) from overwriting. I can insert canaries, but then I have to constantly pay the cost of checking them. Instead of storing the reference count member directly, I could store a pointer to the actual data in a separate mapped write only page, while keeping the structs in read only mapped pages. This will work, the OS will force my application to crash if I try to write to the pointed to data, but indirect storage can be undesirable when trying to write lock free algorithms, because needing to follow another level of indirection can change whether something can be done atomically. Is there any way to mark smaller areas of memory such that writing them will cause your app to blow up? Some platforms have hardware watchpoints, and maybe I could activate one of those with inline assembly, but I'd be limited to only 4 at a time on 32-bit x86 and each one could only cover part of the struct because they're limited to 4 bytes. It'd also make my program painful to debug ;)

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  • Are there size limitations to the .NET Assembly format?

    - by McKAMEY
    We ran into an interesting issue that I've not experienced before. We have a large scale production ASP.NET 3.5 SP1 Web App Project in Visual Studio 2008 SP1 which gets compiled and deployed using a Website Deployment Project. Everything has worked fine for the last year, until after a check-in yesterday the app started critically failing with BadImageFormatException. The check-in in question doesn't change anything particularly special and the errors are coming from areas of the app not even changed. Using Reflector we inspected the offending methods to find that there were garbage strings in the code (which .NET Reflector humorously interpreted as Chinese characters). We have consistently reproduced this on several machines so it does not appear to be hardware related. Further inspection showed that those garbage strings did not exist in the Assemblies used as inputs to aspnet_merge.exe during deployment. aspnet_merge.exe / Web Deployment Project Output Assemblies Properties: Merge all outputs to a single assembly Merge each individual folder output to its own assembly Merge all pages and control outputs to a single assembly Create a separate assembly for each page and control output In the web deployment project properties if we set the merge options to the first option ("Merge all outputs to a single assembly") we experience the issue, yet all of the other options work perfectly! My question: does anyone know why this is happening? Is there a size-limit to aspnet_merge.exe's capabilities (the resulting merged DLL is around 19.3 MB)? Are there any other known issues with merging the output of WAPs? I would love it if any Assembly format / aspnet_merge.exe gurus know about any such limitations like this. Seems to me like a 25MB Assembly, while big, isn't outrageous.

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  • Non-Mainstream Languages, Bad for your resume?

    - by Joe
    Hi folks, I got my BS in Computer Science about seven years ago. I spent two years in neuroscience research and the next three providing what amounts to tech support. But I love computer programming - and I have since written, as a freelancer, non-trivial commercial code in Haskell, Smalltalk, and Objective-C. I used these languages because I find them rewarding, they make me a better programmer and thus, I thought, more attractive to companies. However the polar opposite has occured and I am now unhireable. The freelance market has bottomed out and I am looking for regular employment. But I am being repeatedly turned down, even for entry-level positions, because I don't specifically fit the requirements - eg. Java programmer with 2+ years with JUnit, JavaMail, Servlets etc. And none of the hiring managers, let alone the recruiters, have heard of either Haskell or Smalltalk and more disturbing is their thinly veiled contempt for my background. My question is , how should I market myself to these positions? Is anyone here in a similar position? What should I be doing different professionally? More broadly is this contempt for non-mainstream experience occurring everywhere or just my town? And if there are any hiring managers reading this, I'd love to hear your side. Please be brutally honest. thanks, joe

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  • .post inside jQuery.validator.addMethod always returns false :(

    - by abdullah kahraman
    Hello! I am very new to jQuery and javascript programming. I have a program below that checks whether username is taken or not. For now, the PHP script always returns if(isset($_POST["username"]) )//&& isset($_POST["checking"])) { $xml="<register><message>Available</message></register>"; echo $xml; } Login function works, but username checking doesn't. Any ideas? Here is all of my code: $(document).ready(function() { jQuery.validator.addMethod("checkAvailability",function(value,element){ $.post( "login.php" , {username:"test", checking:"yes"}, function(xml){ if($("message", xml).text() == "Available") return true; else return false; }); },"Sorry, this user name is not available"); $("#loginForm").validate({ rules: { username: { required: true, minlength: 4, checkAvailability: true }, password:{ required: true, minlength: 5 } }, messages: { username:{ required: "You need to enter a username." , minlength: jQuery.format("Your username should be at least {0} characters long.") } }, highlight: function(element, errorClass) { $(element).fadeOut("fast",function() { $(element).fadeIn("slow"); }) }, success: function(x){ x.text("OK!") }, submitHandler: function(form){send()} }); function send(){ $("#message").hide("fast"); $.post( "login.php" , {username:$("#username").val(), password:$("#password").val()}, function(xml){ $("#message").html( $("message", xml).text() ); if($("message", xml).text() == "You are successfully logged in.") { $("#message").css({ "color": "green" }); $("#message").fadeIn("slow", function(){location.reload(true);}); } else { $("#message").css({ "color": "red" }); $("#message").fadeIn("slow"); } }); } $("#newUser").click(function(){ return false; }); });

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  • What's it like being a financial programmer?

    - by Mike
    As a student who's done an internship at a Silicon Valley company(non-financial), I'm curious to know what it's like working for a financial company doing software development. I'd expect the hours to be longer, and the pay to be higher. Specifically, I have the following questions: What's the work/life balance really like? Are you expected to work 80 hours a week most weeks? For those who have worked in non-financial software engineering jobs, how does being a financial software engineer compare in terms of work/life balance? How much does it pay? I'm curious as to starting(i.e. just got a BS) pay, as well as "top out" pay. (I'd prefer concrete numbers - ballpark is fine). Also, bonuses would be useful information. What jobs do financial programmers typically have? Are most just general software engineers, or do people typically have very specialized(i.e. AI or systems) backgrounds? Also, do most programmers have PhDs? Are programmers typically required to be at work, or are financial companies generally flexible about letting programmers work from home? When at work, do programmers have to dress formally? What are the technology environments like? Are finance companies using state-of-the-art hardware and software, or are they generally more conservative in upgrading their equipment? What programming languages are typically used? If VBA(shudder) is used, is it a large part of a finance company's workflow? If you could turn back the clock, would you still be a financial programmer? I'm going to keep this post open a little bit longer to get some more responses.

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  • Interactive Web Collaboration Platform

    - by user1477586
    I am currently unsatisfied with most, if not all, web-based collaboration tools I've ever used. Examples of what I'm considering a "web-based collaboration tool" are TWiki, WebEx, etc. What I have in mind of developing is to develop my own. The target "market" is for software/hardware developers who will likely be working on separate projects linked by a common goal. Example: You work at a company who is designing a brand new printer. So, one man is working on the ink cartridge, another on the paper feed, one on the circuitry of the printer and one more is working on the drivers. What I would like to make (unless it already exists) is a website that, upon loading, presents the user with a web that has each project within it's own bubble, graphically. These bubbles would all be linked to the central bubble of "[Company Name]". Upon selecting an individual bubble the browser would focus and zoom in on that project bubble and expand more information (in bullets or with more affiliated bubbles) about subprojects, progress, setbacks, etc. Then, at a terminal "node" (i.e. a bubble with no sub-bubbles) a selection would then load a page with information relevant to that node. That's a lot of monologue. In short, I want to know how I might approach this. My background is with algorithmic use of Python and C++. I've never done interactive web design like this; though, I have gone through the W3C tutorials on HTML4/5. I'm willing to learn a new language I'm just wondering which language/set of languages seem(s) most appropriate for this project. Thanks, world, for imparting your knowledge to me. An example of what the start page might look like is:

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  • Manually Writing the HTML in TWebBrowser Pt. 2

    - by nomad311
    As the name suggests this is a continuation (sort of) of http://stackoverflow.com/questions/2784679/manually-writing-the-html-in-twebbrowser This time around I'm trying to add some auto-refresh logic to the HTML I get. I have pieced together an approach from several sources (see below). In short, I am trying to locate the title node and add a meta node after it (in the HTML head node). But, I get an access violation. Here is the source: iHtmlDoc := IHTMLDocument3(WebBrowser1.Document); iHtmlEleTitle := IHTMLElement2(iHtmlDoc.getElementsByName('title').item(0, 0)); iHtmlEle := IHTMLElement2(IHTMLDocument2(iHtmlDoc).createElement(Format('<meta http-equiv="refresh" content="%d">', [1]))); iHtmlEleTitle.insertAdjacentElement('afterEnd', IHTMLElement(iHtmlEle)); And A (technically not functionally) different way of doing it ...casting is slightly different here: IHTMLElement2(IHtmlDocument3(WebBrowser1.Document).getElementsByName('title').item(0, 0)).insertAdjacentElement('afterEnd', IHTMLDocument2(WebBrowser1.Document).createElement(Format('<meta http-equiv="refresh" content="%d">', [VPI_ISSUANCE_AUTO_RELOAD]))); Again all I get from Delphi is a access exception, and I fished through MSDN documentation on it, but now I'm hoping someone out there has gone through the same and has some insight. Any help? Sources (I think this is all of them): http://webdesign.about.com/od/metataglibraries/a/aa080300a.htm (auto-reload) http://delphi.about.com/od/adptips2005/qt/webbrowserhtml.htm (web browser document as an HTML document) http://msdn.microsoft.com/en-us/library/system.windows.forms.htmlelement.insertadjacentelement(VS.80).aspx (GetElementsByName) http://www.experts-exchange.com/Web_Development/Components/ActiveX/Q_26131034.html (insertAdjacentElement) http://www.experts-exchange.com/Programming/Languages/Pascal/Delphi/Q_23407977.html (GetElementsByName)

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  • 3 Servers, is this is a cluster?

    - by Andy Barlow
    Hello, At the moment I have one Ubuntu server, 9.10, running with a simple Samba share, a mail server, DNS server and DHCP server. Mostly its just there for file sharing and email server. I also have 2 other servers that are exactly the same hardware and spec as the first, which have an rsync set up to retrieve the shared folders and backs them up. However, if the first server goes down, all of our shares disappear along with our mail and the system must be rebuilt. Also I tend to find if people are downloading a large amount from the file server, no-one can access there emails - especially in the morning when everyone is signing in at once. Would it be more beneficial for me to have all 3 servers, all running the same services, doing the same thing with some sort of cluster with load balancing? I'm not really sure where to begin looking, or how to go about such a setup where 3 servers are all identical, but perhaps one acts as the main load balancer?? If someone can point me in the right direction, or if this simply sounds like one of those Enterprise Cloud's that is now a default setup in Ubuntu Server 9.10+, then I'll go down that route. Cheers in advance. Andy

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  • Declaration of arrays before "normal" variables in c?

    - by bjarkef
    Hi We are currently developing an application for a msp430 MCU, and are running into some weird problems. We discovered that declaring arrays withing a scope after declaration of "normal" variables, sometimes causes what seems to be undefined behavior. Like this: foo(int a, int *b); int main(void) { int x = 2; int arr[5]; foo(x, arr); return 0; } foo sometimes is passed a pointer as the second variable, that does not point to the arr array. We verify this by single stepping through the program, and see that the value of the arr variable in the main scope is not the same as the value of the b pointer variable in the foo scope. And no, this is not really reproduceable, we have just observed this behavior once in a while. Changing the example seems to solve the problem, like this: foo(int a, int *b); int main(void) { int arr[5]; int x = 2; foo(x, arr); return 0; } Does anybody have any input or hints as to why we experience this behavior? Or similar experiences? The MSP430 programming guide specifies that code should conform to the ANSI C89 spec. and so I was wondering if it says that arrays has to be declared before non-array variables? Any input on this would be appreciated.

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  • A business Case for Enterprise Python

    - by Srirangan
    Hi all, This will not be a "programming" question but more technology / platform related question. I'm trying to figure out whether Python can be a suitable Java alternative for enterprise / web applications. Which are the ideal cases where you would prefer to use Python instead of Java? How would a typical Python web application (databases/sessions/concurrency) perform as compared to a typical Java application? How do specific Python frameworks square up against Java based frameworks (Spring, SEAM, Grails etc.)? For businesses, switching from the Java infrastructure to a Python infrastructure .. is it too hard/expensive/resource intensive/not viable? Also shed some light on the business case for providing a Python + Google AppEngine based solution to the end customer. Will it be cost effective in an typical scenario? Sorry if I am asking too wide a question, I would have liked to keep it specific, but I need your help to evaluate Python as a whole from the perspectives of the programmers, service providing company and end business customer. For an SME, a Python/GoogleAppEngine based technology stack is a clear scalable and affordable platform. But what about a large MNC that already has a lot invested in Java. Thank you so much. I am researching this myself and will gladly share my conclusions here! Thank you, Srirangan

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  • Playing a .TS file on iOS

    - by Jonathan Grynspan
    We're working with some hardware that produces files in the .TS format, and we'd like to play them on an iOS device. (The files are internally consistent with what iOS supports--MPEG-4 video, AAC audio.) We've been investigating three options so far: Roll our own integrated HTTP Live Streaming server and serve up a faux M3U8 playlist from within the app. This... doesn't seem to want to play nice, and we've had mixed luck actually getting the .TS files to play on devices. Unwrap the MPEG-4 and AAC data from the TS file and re-wrap it as MP4. This, I'm told, is exceedingly difficult to do, and I haven't found anything useful online that could shed light on how to do it. We've got code in the pipeline to do it but it won't be ready until long after we need it. If we could do it, I could easily subclass NSURLProtocol and have it working within a matter of hours minutes. Use FFmpeg to implement option #2. FFmpeg seems like a possible solution but it isn't configured to build for iOS and I don't have the background to get it working (whereas the rest of our engineers don't have the Apple background needed.) I think #2 is our best bet, but as I don't know the ins and outs of MPEG-2 TS and MPEG-4, I don't have the ability to put it together myself. Does anybody have any insight into this problem? Perhaps some experience playing local TS files on iOS, or some tips on converting from TS to MP4?

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  • Nonetype object has no attribute '__getitem__'

    - by adohertyd
    I am trying to use an API wrapper downloaded from the net to get results from the new azure Bing API. I'm trying to implement it as per the instructions but getting the runtime error: Traceback (most recent call last): File "bingwrapper.py", line 4, in <module> bingsearch.request("affirmative action") File "/usr/local/lib/python2.7/dist-packages/bingsearch-0.1-py2.7.egg/bingsearch.py", line 8, in request return r.json['d']['results'] TypeError: 'NoneType' object has no attribute '__getitem__' This is the wrapper code: import requests URL = 'https://api.datamarket.azure.com/Data.ashx/Bing/SearchWeb/Web?Query=%(query)s&$top=50&$format=json' API_KEY = 'SECRET_API_KEY' def request(query, **params): r = requests.get(URL % {'query': query}, auth=('', API_KEY)) return r.json['d']['results'] The instructions are: >>> import bingsearch >>> bingsearch.API_KEY='Your-Api-Key-Here' >>> r = bingsearch.request("Python Software Foundation") >>> r.status_code 200 >>> r[0]['Description'] u'Python Software Foundation Home Page. The mission of the Python Software Foundation is to promote, protect, and advance the Python programming language, and to ...' >>> r[0]['Url'] u'http://www.python.org/psf/ This is my code that uses the wrapper (as per the instructions): import bingsearch bingsearch.API_KEY='abcdefghijklmnopqrstuv' r = bingsearch.request("affirmative+action")

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  • Using multiple sockets, is non-blocking or blocking with select better?

    - by JPhi1618
    Lets say I have a server program that can accept connections from 10 (or more) different clients. The clients send data at random which is received by the server, but it is certain that at least one client will be sending data every update. The server cannot wait for information to arrive because it has other processing to do. Aside from using asynchronous sockets, I see two options: Make all sockets non-blocking. In a loop, call recv on each socket and allow it to fail with WSAEWOULDBLOCK if there is no data available and if I happen to get some data, then keep it. Leave the sockets as blocking. Add all sockets to a fd_set and call select(). If the return value is non-zero (which it will be most of the time), loop through all the sockets to find the appropriate number of readable sockets with FD_ISSET() and only call recv on the readable sockets. The first option will create a lot more calls to the recv function. The second method is a bigger pain from a programming perspective because of all the FD_SET and FD_ISSET looping. Which method (or another method) is preferred? Is avoiding the overhead on letting recv fail on a non-blocking socket worth the hassle of calling select()? I think I understand both methods and I have tried both with success, but I don't know if one way is considered better or optimal. Only knowledgeable replies please!

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  • TCL TDom: Looping through Objects

    - by pws5068
    Using TDom, I would like to cycle through a list of objects in the following format: <object> <type>Hardware</type> <name>System Name</name> <description>Basic Description of System.</description> <attributes> <vendor>Dell</vendor> <contract>MM/DD/YY</contract> <supportExpiration>MM/DD/YY</supportExpiration> <location>Building 123</location> <serial>xxx-xxx-xxxx</serial> <mac>some-mac-address</mac> </attributes> </object> <object> <type>Software</type> <name>Second Object</name> ... Then I use TDom to make a list of objects: set dom [dom parse $xml] set doc [$dom documentElement] set nodeList [$doc selectNodes /systems/object] So far I've done this to (theoretically) select every "Object" node from the list. How can I loop through them? Is it just: foreach node $nodeList { For each object, I need to retrieve the association of each attribute. From the example, I need to remember that the "name" is "System Name", "vendor" is "Dell", etc. I'm new to TCL but in other languages I would use an object or an associative list to store these. Is this possible? Can you show me an example of the syntax to select an attribute in this manner?

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  • Adding libraries to a project in xcode - symbols not found

    - by kudorgyozo
    I am trying to make an iphone app in xcode that uses pjsip. The problem is I don't know how to link the libraries. I have the ARM version of the libraries in this folder in mac os x. /Users/kudorgyozo/pjsip_iphone In Xcode: I have specified the library and header search paths like this: for includes: /Users/kudorgyozo/pjsip_iphone/pjlib/include /Users/kudorgyozo/pjsip_iphone/pjlib-util/include /Users/kudorgyozo/pjsip_iphone/pjmedia/include /Users/kudorgyozo/pjsip_iphone/pjnath/include /Users/kudorgyozo/pjsip_iphone/pjsip/include for libraries: /Users/kudorgyozo/pjsip_iphone/pjlib/lib /Users/kudorgyozo/pjsip_iphone/pjlib-util/lib /Users/kudorgyozo/pjsip_iphone/pjmedia/lib /Users/kudorgyozo/pjsip_iphone/pjnath/lib /Users/kudorgyozo/pjsip_iphone/pjsip/lib and then using the "Other linker flags" : -lpj-arm-apple-darwin9 -lpjlib-util-arm-apple-darwin9 -lpjmedia-arm-apple-darwin9 -lpjmedia-audiodev-arm-apple-darwin9 -lpjmedia-codec-arm-apple-darwin9 -lpjsdp-arm-apple-darwin9 -lpjnath-arm-apple-darwin9 -lpjsip-arm-apple-darwin9 -lpjsip-simple-arm-apple-darwin9 -lpjsip-ua-arm-apple-darwin9 -lpjsua-arm-apple-darwin9 Is this OK like this? Because it gives me symbol(s) not found errors. I think no symbol is found from the "included" libraries. I don't know what is wrong i'm just beginning to understand how building an app works under linux based systems i've only done programming in C# before.

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  • Code Golf: Shortest Turing-complete interpreter.

    - by ilya n.
    I've just tried to create the smallest possible language interpreter. Would you like to join and try? Rules of the game: You should specify a programming language you're interpreting. If it's a language you invented, it should come with a list of commands in the comments. Your code should start with example program and data assigned to your code and data variables. Your code should end with output of your result. It's preferable that there are debug statements at every intermediate step. Your code should be runnable as written. You can assume that data are 0 and 1s (int, string or boolean, your choice) and output is a single bit. The language should be Turing-complete in the sense that for any algorithm written on a standard model, such as Turing machine, Markov chains, or similar of your choice, it's reasonably obvious (or explained) how to write a program that after being executred by your interpreter performs the algorithm. The length of the code is defined as the length of the code after removal of input part, output part, debug statements and non-necessary whitespaces. Please add the resulting code and its length to the post. You can't use functions that make compiler execute code for you, such as eval(), exec() or similar. This is a Community Wiki, meaning neither the question nor answers get the reputation points from votes. But vote anyway!

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