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  • Is there a c++ library that provides functionality to execute an external program and read its outpu

    - by BD at Rivenhill
    Basically, I'm looking for something that will allow me to replicate the following Perl code: my $fh = new FileHandle; $fh->open("foo |"); while (<$fh>) { # Do something with this line of data. } This is in the context of Linux, so a library that is specific to Windows will not help. I know how to write a program that does fork/exec/dup2 and all that basic shell-type jazz, but there are some fiddly details involving terminals that I don't feel like messing around with (and I don't have a copy of "Advanced Programming in the UNIX Environment" or a similar reference handy), so I'm hoping that someone has already solved this problem.

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  • Convert a string representation of a hex dump to a byte array using Java?

    - by ravigad
    I am looking for a way to convert a long string (from a dump), that represents hex values into a byte array. I couldn't have phrased it better than the person that posted the same question here: http://www.experts-exchange.com/Programming/Programming_Languages/Java/Q_21062554.html But to keep it original, I'll phrase it my own way: suppose I have a string "00A0BF" that I would like interpreted as the byte[] {0x00,0xA0,0xBf} what should I do? I am a Java novice and ended up using BigInteger and watching out for leading hex zeros. But I think it is ugly and I am sure I am missing something simple...

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  • Database system that is not relational.

    - by paan
    What are the other types of database systems out there. I've recently came across couchDB that handles data in a non relational way. It got me thinking about what other models are other people is using. So, I want to know what other types of data model is out there. (I'm not looking for any specifics, just want to look at how other people are handling data storage, my interest are purely academic) The ones I already know are: RDBMS (mysql,postgres etc..) Document based approach (couchDB, lotus notes) Key/value pair (BerkeleyDB)

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  • Finding relative libraries when using symlinks to ruby executables

    - by dgtized
    Imagine you have an executable foo.rb, with libraries bar.rb layed out in the following manner: <root>/bin/foo.rb <root>/lib/bar.rb In the header of foo.rb you place the following require to bring in functionality in bar.rb: require File.dirname(__FILE__)+"../lib/bar.rb" This works fine so long as all calls to foo.rb are direct. If you put as say $HOME/project, and symlink foo.rb into $HOME/usr/bin, then __FILE__ resolves to $HOME/usr/bin/foo.rb, and is thus unable to locate bar.rb in relation to the dirname for foo.rb. I realize that packaging systems such as rubygems fix this by creating a namespace to search for the library, and that it is also possible to adjust the load_path using $: to include $HOME/project/lib, but it seems as if a more simple solution should exist. Has anyone had experience with this problem and found a useful solution or recipe?

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  • What is the use of commit messages?

    - by eteubert
    Hi folks, I struggled asking that question but here it is. I am using source control since several years for multiple projects using different systems (svn, hg, git) and I learned how to improve my messages by following guidelines etc. But as far as I can remember I never ever had a look at them afterwards. So ... how do you profit from your own commit messages? When I need to go back because I smashed something and need a fresh start, I usually just go back to the latest "node" (where I started or merged a branch). Do I write those messages just for people monitoring the project who are curious what is going on? Regards

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  • Python design mistakes

    - by Andrea
    A while ago, when I was learning Javascript, I studied Javascript: the good parts, and I particularly enjoyed the chapters on the bad and the ugly parts. Of course, I did not agree with everything, as summing up the design defects of a programming language is to a certain extent subjective - although, for instance, I guess everyone would agree that the keyword with was a mistake in Javascript. Nevertheless, I find it useful to read such reviews: even if one does not agree, there is a lot to learn. Is there a blog entry or some book describing design mistakes for Python? For instance I guess some people would count the lack of tail call optimization a mistake; there may be other issues (or non-issues) which are worth learning about.

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  • Books on data-intensive enterprise integration patterns

    - by Tristan
    I'm trying to understand design patterns used by data-intensive enterprise applications. A classic example is the financial industry, where system must consume, analyze, and execute on real-time financial data while providing information and configuration options to a broad set of traders and analysts. One can imagine similar system in airlines, major supply chain operations, and utility providers. Are there good books that provide and inside view of how these systems work? Enterprise Integration Patterns is one example, but I'm looking for something with more real-world applications, particularly in finance.

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  • C++ Types Impossible to Name

    - by Kirakun
    While reading Wikipedia's page on decltype, I was curious about the statement, Its [decltype's] primary intended use is in generic programming, where it is often difficult, or even impossible, to name types that depend on template parameters. While I can understand the difficulty part of that statement, what is an example where there is a need to name a type that cannot be named under C++03? EDIT: My point is that since everything in C++ has a declaration of types. Why would there ever be a case where it is impossible to name a type? Furthermore, aren't trait classes designed to yield type informations? Could trait classes be an alternative to decltype?

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  • Conditionally setting the font color of an item in a drop down box in JSF

    - by Greg
    I'm a newbie to web programming, so please bear with me. I am using JSF 1.2 and I want to conditionally set the color of the items in my drop down list. In other words, I have a collection of items that, along with a key and a value, also have a boolean property, warning, that is dynamically set by user action. I want the drop down to show all of the items, but those whose warning property is set to true should be displayed in red. I assume I have to extend the SelectItem class to add in the boolean property. How do I then conditionally set the color of the font of those items whose warning property is set to true in my JSP pages? Thanks in advance

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  • How is fseek() implemented in the filesystem?

    - by pajton
    This is not a pure programming question, however it impacts the performance of programs using fseek(), hence it is important to know how it works. A little disclaimer so that it doesn't get closed. I am wondering how efficient it is to insert data in the middle of the file. Supposing I have a file with 1MB data and then I insert something at the 512KB offset. How efficient would that be compared to appending my data at the end of the file? Just to make the example complete lets say I want to insert 16KB of data. I understand the answer varies depending on the filesystem, however I assume that the techniques used in common filesystems are quite similar and I just want to get the right notion of it.

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  • I need to pad IP addresses with Zeroes for each octet

    - by Felipe Alvarez
    Starting with a string of an unspecified length, I need to make it exactly 43 characters long (front-padded with zeroes). It is going to contain IP addresses and port numbers. Something like: ### BEFORE # Unfortunately includes ':' colon 66.35.205.123.80-137.30.123.78.52172: ### AFTER # Colon removed. # Digits padded to three (3) and five (5) # characters (for IP address and port numbers, respectively) 066.035.05.123.00080-137.030.123.078.52172 This is similar to the output produced by tcpflow. Programming in Bash. I can provide copy of script if required. If it's at all possible, it would be nice to use a bash built-in, for speed. Is printf suitable for this type of thing?

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  • What are the things Java got right?

    - by hamletdarcy
    What are the things that Java (the language and platform) got categorically right? In other words, what things are more recent programming languages preserving and carrying forward? Some easy answer are: garbage collection, a VM, lack of pointers, classloaders, reflection(?) What about language based answers? Please don't list the things Java did wrong, just right. (note by Mark Harrison) This is an interesting and useful question, especially for those of us who don't use java regularly. I'm voting for reopening. Please don't close as argumentative, as it doesn't seem to be causing any arguments.

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  • Xcode 3.2 not recompiling changed files

    - by Jason
    I've been programming a new iPhone application and everything has been chugging along fine, until this afternoon when I noticed that any changes I was making were not being reflected in the actual app! Even code that throws errors isn't getting picked up by the compiler. To get around this, I have taken to the following procedure: Finish making my edits, and add code to the file which will always throw a compiler error. Right-click the file I have just edited, and hit "Compile" to just compile that one file; it will throw the error. Remove the error-producing code, and again right-click and "Compile" the one file. Build the whole project This is quite annoying, and I can't figure out why this would suddenly happen to my Xcode project. Any thoughts on what could be causing this, and how to fix it?

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  • C# (With .NET & Visual Studio) WebForms - How can I get the title of a page ..?

    - by Ashley Davies
    Prety long question; How can I do the following in C#: Open a webpage (Prefferably not visible) Check whether the page redirects to a different page (Site is down, 404, etc.) Check if the title is not equal to a said string Then seperately, (They need to click a confirm button) open their browser, and go to the adress of the first (It'll be the only one) hyperlink on the site. I literally have been looking on google for ages and haven't found anything similar to what I need. Whether you give me a link to a site with a tutorial on this area of programming or actual source code doesn't make a difference to me.

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  • Dropdowns don't work on webOS with PhoneGap?

    - by Steve Nay
    I'm trying to use a dropdown in a PhoneGap app I'm writing. It uses a simple <select>: <select> <option value="1">First</option> <option value="2">Second</option> </select> This works fine on Android and the iPhone (including behaving like a native drop-down would on those systems). However, it doesn't appear to work on webOS (neither the Palm Pre itself nor the emulator). The <select> displays properly on the screen, but when I tap on it, nothing happens--I'm not able to make a selection from the dropdown. Why might this be?

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  • Are MongoDB and CouchDB perfect substitutes?

    - by raoulsson
    I haven't got my hands dirty yet with neither CouchDB nor MongoDB but I would like to do so soon... I also have read a bit about both systems and it looks to me like they cover the same cases... Or am I missing a key distinguishing feature? I would like to use a document based storage instead of a traditional RDBMS in my next project. I also need the datastore to handle large binary objects (images and videos) automatically replicate itself to physically separate nodes rendering the need of an additional RDBMS superfluous Are both equally well suited for these requirements? Thanks!

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  • Mono on OS X Compatible with MSVC 2010 peers?

    - by Chris
    I'm to begin .NET development at work but have the option of using MonoDevelop/Mono on OS X instead of MSVC 2010 on Windows and would prefer it because of my familiarity with OS X. We are likely going to use a number of popular frameworks, such as NHibernate and Castle DI - my question to those of you familiar with .NET development and Mono: will I be at much of a disadvantage? Are there strong incompatibilities or, with some "paper cuts", the two systems are roughly compatible? Again, my colleagues will be using MSVC 2010 and we intend on working on the same codebases together. Thanks for any insight you can give to this .NET newbie. EDIT: I should note I'll primarily be doing development with MVC 2, which I understand does work with Mono, and will have some leeward in choosing frameworks, i.e. I can avoid highly incompatible frameworks.

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  • drawbacks of storing all ''things' in a central table

    - by naiquevin
    Hi, I am not sure if there is a term to describe this, but I have observed that content management systems store all kinds of data in a single table with their bare minimum properties while the meta data is stored in another table in form of key value pairs. for eg. everything (blog posts, pages, images, events etc) is stored in one table and considered as a post. I understand that this allows for abstraction and easy extensibility we are considering designing our new project this way. It is not exactly a CMS but we plan to keep adding modules to it in stages. Lets say initially there will be only posts and images on which comments can be posted. Later on we might add videos which will also have the commenting feature. what are the drawbacks of this approach ? and will it work for a requirement like ours ? Thanks

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  • How do you compare music data

    - by Chris
    i want to write an app to rename sort and organize my music library (mp3's, wav's, flac's). I wanted to take a portion of the song, say the first minutes, and compare that to a database and then retrieve the song name and tag information. I have heard that you can do this with last.fm but a look through their api info didn't help. My question is, what is this called so i can google it better? nothing i am trying is helping much. This would be similar to the shazam android app. My prefered language would be java, so i can run it on a few operating systems easier, but that might be subject to change depending on how i can do it. Thanks

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  • GoTo statements and alternatives in VB.NET

    - by qais
    I've posted a code snippet on another forum asking for help and people pointed out to me that using GoTo statements is very bad programming practice. I'm wondering: why is it bad? What alternatives to GoTo are there to use in VB.NET that would be considered generally more of a better practice? Consider this snippet below where the user has to input their date of birth. If the month/date/year are invalid or unrealistic(using if statements checking the integer inputs size, if there's a better way to do this, I'd appreciate if you could tell me that also :D) How would I be able to loop back to ask the user again? retryday: Console.WriteLine("Please enter the day you were born : ") day = Console.ReadLine If day > 31 Or day < 1 Then Console.WriteLine("Please enter a valid day") GoTo retryday End If

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  • databind a DropDownList control with a list of all sub directories that exist in a particular direct

    - by sushant
    I am wanting to databind a DropDownList control with a list of all sub directories that exist in a particular directory on the server. The directory I want to search is in the root of the application. I am fairly new to programming and I'm not sure where to even start. I found this code on a website: Dim root As String = "C;\" Dim folders() As String = Directory.GetDirectories(root) Dim sb As New StringBuilder(2048) Dim f As String For Each f In folders Dim foldername As String = Path.GetFileName(f) sb.Append("<option>") sb.Append(foldername) sb.Append("</option>") Next Label3.Text = "<select runat=""sever"" id=""folderlist""" & sb.ToString() & "</select>" I guess this is vb. but my tool is in asp, so is their something similar in vbscript so that I can use it.

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  • In Flash Actionscript 3.0 how do I create smooth keyboard controls for player movement?

    - by Reid
    I am a beginner in Flash Actionscript 3.0 programming. I am trying to create smooth keyboard controls for player movement in a game. I'm currently using addEventListener(KeyboardEvent.KEY_DOWN) listening for a keyboard key press and then within the handler function moving a graphic by adding a number to its .x or .y property. This creates a slow, sluggish jerk at the beginning. I know there's a smoother, more responsive way to do this but have no idea where to begin. Any help would be appreciated!

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  • Convert Yes/No/Null from SQL to True/False in a DataTable

    - by Scott Chamberlain
    I have a Sql Database (which I have no control over the schema) that has a Column that will have the varchar value of "Yes", "No", or it will be null. For the purpose of what I am doing null will be handled as No. I am programming in c# net 3.5 using a data table and table adapter to pull the data down. I would like to directly bind the column using a binding source to a check box I have in my program however I do not know how or where to put the logic to convert the string Yes/No/null to boolean True/False; Reading a null from the SQL server and writing back a No on a update is acceptable behavior. Any help is greatly appreciated. EDIT -- This is being developed for windows.

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  • How can I have a Windsor IoC container that can be shared amongst my classes but not shared across m

    - by Si Keep
    I am building a set of class libraries that produce office open xml based reports and I am using a static Windsor IoC container. My problem is that one possible entry point to the reporting system is via a web front end which means that the reporting systems static IoC Container is being shared amongst multiple web requests which causes exceptions as for each new request the reporting system is trying re-register components in Windsor that were already registered by an earlier request. I dont want to move the registration into the web app global.asax as my reporting system will no longer be stand-alone. How can I have a Windsor IoC container that can be shared amongst my reporting classes but not shared across multiple web requests?

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  • Using custom HTML attributes for JavaScript purposes?

    - by user1103990
    One of my colleagues doesn't like to use HTML classes and ids for javascript/jQuery purpose. Therefore I've seen that he had created custom html attribute such as <div id="myid" class="cssClasses ..." [some-purpose-id]="mycustomId">...</div> I asked him if it was really a good idea and he replied that he considers that classes and Ids should be reserved for styling. Personally, I would have used classes. Some classes would have been used for styling, and some other classes would have been used for programming (jQuery selectors). The idea is to keep things appart also. And of course jQuery could set styling classes but if possible not use them for selection. Of course I also use id when appropriate but since an id is unique on a page, I like to do generic stuff using classes. I would like to know you opinions on the better approach (if there is one). Thank you.

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