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  • Build Environment setup - Using .net, java, hudson, and ruby - Could really use a critique

    - by Jeff D
    I'm trying to figure out the best way to stitch together a fast, repeatable, unbreakable build process for the following environment. I've got a plan for how to do it, but I'd really appreciate a critique. (I'd also appreciate some sample code, but more on that later) Ecosystem - Logical: Website - asp.net MVC 2, .net 3.5, Visual Studio 2010. IIS 6, Facebook iframe application application. This website/facebook app uses a few services. An internal search api, an internal read/write api, facebook, and an IP geolocation service. More details on these below Internal search api - .net, restful, built using old school .ashx handlers. The api uses lucene, and a sql server database behind the scenes. My project won't touch the lucene code, but does potentially touch the database and the web services. internal read/write api - java, restful, running on Tomcat Facebook web services A mocking site that emulates the internal read/write api, and parts of the facebook api Hudson - Runs unit tests on checkin, and creates some installers that behave inconsistently. Ecosystem - Physical: All of these machines can talk to one another, except for Hudson. Hudson can't see any of the target machines. So code must be pulled, rather than pushed. (Security thing) 1. Web Server - Holds the website, and the read/write api. (The api itself writes to a replicated sql server environment). 2. Search Server - Houses the search api. 3. Hudson Server - Does not have permissions to push to any environment. They have to pull. 4. Lucene Server 5. Database Server Problem I've been trying to set this site up to run in a stress environment, but the number of setup steps, the amount of time it takes to update a component, the black-box nature of the current installers, and the time it takes to generate data into the test system is absolutely destroying my productivity. I tweak one setting, have to redeploy, restart in a certain order, resetup some of the settings, and rebuild test data. Errors result in headscratching, and then basically starting over. Very bad. This problem is complicated further by my stress testing. I need to be able to turn on and off different external components, so that I can effectively determine the scalability of each piece. I've got strategies in place for how to do that for each dependency, but it further complicates my setup strategy, because now each component has 2 options. A mock version, or a real version. Configurations everywhere must be updated accordingly. Goals Fast - I want to drop this from a 20 minute exercise when things go perfectly, to a 3 minute one Stupid simple - I want to tell the environment what to do with as few commands as possible, and not have to remember how to stitch the environments together Repeatable - I want the script to be idempotent. Kind of a corollary to the Stupid Simple thing. The Plan So Far Here's what I've come up with so far, and what I've come looking for feedback on: Use VisualStudio's new web.config transformations to permit easily altering configs based on envrionment. This solution isn't really sufficient though. I will leave web.config set up to let the site run locally, but when deploying elsewhere, I have as many as 6 different possible outputs for the stress environment alone (because of the mocks of the various dependencies), let alone the settings for prod, QA, and dev. Each of these would then require it's own setup, or a setup that would then post-process the configs. So I'm currently leaning toward just having the dev version, and a version that converts key configuration values into a ruby string interpolation syntax. ({#VAR_NAME} kinda thing) Create a ruby script for each server that is essentially a bootstrapping script. That is to say, it will do nothing but load the ruby code that does the 'real' work from hudson/subversion, so that the script's functionality can evolve with the application, making it easy to build the site at any point in time by reference the appropriate version of the script. So in a nutshell, this script loads another script, and runs it. The 'real' ruby script will then accept commandline parameters that describe how the environment should look. From there, 1 configuration file can be used, and ruby will download the current installers, run them, post-process the configs, restart IIS/Tomcat, and kick off any data setup code that is needed. So that's it. I'm in a real time crunch to get this site stress-tested, so any feedback that you think could abbreviate the time this might take would be appreciated. That includes a shameless request for sample ruby code. I've not gotten too much further than puts "Hello World". :-) Just guidance would be helpful. Is this something that Rake would be useful for? How would you recommend I write tests for this animal? (I use interfaces and automocking frameworks to mock out things like http requests in .net. With ducktyping, it seems that this might be easier, but I don't know how to tell my code to use a fake duck in test, but a real one in practice) Thanks all. Sorry for such such a long-winded, open-ended question.

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  • image scaling with C

    - by sa125
    Hi - I'm trying to read an image file and scale it by multiplying each byte by a scale its pixel levels by some absolute factor. I'm not sure I'm doing it right, though - void scale_file(char *infile, char *outfile, float scale) { // open files for reading FILE *infile_p = fopen(infile, 'r'); FILE *outfile_p = fopen(outfile, 'w'); // init data holders char *data; char *scaled_data; // read each byte, scale and write back while ( fread(&data, 1, 1, infile_p) != EOF ) { *scaled_data = (*data) * scale; fwrite(&scaled_data, 1, 1, outfile); } // close files fclose(infile_p); fclose(outfile_p); } What gets me is how to do each byte multiplication (scale is 0-1.0 float) - I'm pretty sure I'm either reading it wrong or missing something big. Also, data is assumed to be unsigned (0-255). Please don't judge my poor code :) thanks

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  • ASP.Net ITemplate - how do i get the content inside

    - by Mahes
    i have situation where in i would like to read the content of the ITemplate. for example i have something like <WD:PopUpPanel runat="server" ID="MyPoPUp"> <InitScript> // javascript document.getElementByID('urName').value = 'enter your name'; </InitScript> <Content> Name:<asp:TextBox runat="Server" ID="urName"/> </Content> </WD:PopUpPanel> basically the contents inside the InitScript is some javascript, which i want to use in ScriptManager.RegisterScript. so my question is how do i define InitScript??? i tried public ITemplate InitScript; but this give CompiledTemplateBuilder object, how do i read the content inside InitScript ??? thanks for reading...

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  • Continuing education with Visual Basic 9

    - by TSSH
    I am completely new to programming and starting my education with visual basic 9 and SQL. I have read Visual Basic, in easy steps, 2nd edition by Mike Mcgrath. Although it was very easy to understand, it only gave me an introduction to learning VB. I'm looking for something more in depth, albeit for a beginner. I've read through the questions with a VB and book tag. Unfortunately, most of what I've found here references VB 6 and VB 8. Any recommendations? I cannot afford to create a library or college at the moment. So, I need to make sure that what I do buy counts. Thanks for any suggestions!

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  • Xcode & passing command line arguments

    - by Brisco
    I just started working with C & Xcode and I've run into a little difficulty. All I want to do is read a file from the command line and see the output in the terminal. I think my problem lies with the path to the file that I want to read in. I'm using a Mac and the file is on my desktop, so the path should be Users/myName/Desktop/words.txt. Is this correct? This is my code: #import <Foundation/Foundation.h> int main (int argc, const char* argv[]){ if(argc == 1){ NSLog(@" you must pass at least one arguement"); return 1; } NSLog(@"russ"); FILE* wordFile = fopen(argv[1] , "r"); char word[100]; while (fgets(word,100,wordFile)) { NSLog(@" %s is %d chars long", word,strlen(word)); } fclose(wordFile); return 0; }//main

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  • Repair bad character due to encoding problem

    - by remi bourgarel
    Hi all, Recently we had an encoding problem in our system : If we had the string "æ" in our db ,it became "æ" on our web pages. Now this problem is solved, but the problem is that now we have a lot of "æ" in our database : users didn't see and validate pre-filled form with these characters. I found that If you read in utf 8 C3A6 you'll get "æ", if you read it in ascii you'll get "æ". It's strange because if I execute "select convert(varbinary(40),N'æ'),convert(varbinary(40),'æ')" I don't have the same result... Do you have any idea on how I can fix my database (ie change all "æ" to "æ") ? thx

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  • Difference between Document-oriented-DB and Bigtable clones

    - by chen
    We are looking for a suitable storage engine for our weblog history data. We looked at Bigtable's paper and understand it is suitable to us well. However, I also understand that Document-oriented-DB such as MongoDB seems to provide a little more powerful schema power -- i.e, it can model our data as well. I wonder how nowadays ppl choose a scalable NoSQL DB --- I read enough articles like "we looked at A, B and C, and we decided to use C". But I'd like to see some benchmark number. What I am saying is that if MongoDB and the like can provide same level of performance as Bigtable clones, why don't web companies choose it (preparing to deal with various potentially more complex data problem)? Thanks, By the way, I read an article (which convinced me at the moment) saying Cassandra does not fit the M/R operation, any comments?

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  • Change My.Settings ConnectionString in runtime?

    - by Sultanen
    I have a ClickOnce deployment where i have a INI-settings file on the network file with "global" settings that is supposed to affect the program on all client computers. The problem i have is that i whant to have the Database connectionString stored in this INI file and have it read and stored in the My.Settings ConnectionString at program startup. How do i do this? The ConnectionString setting is Application scoped and therefore Read-Only, if i try to set it by My.Settings("ConnectionString") = "Source=server;Initial Catalog=database;Integrated Security=True" I get a runtime error: An error occurred creating the form. See Exception.InnerException for details. The error is: The type initializer for 'DB_lib.DB_LINQ' threw an exception. [EDIT] I got rid of the error by using the My.Settings("ConnectionString") = "Source=server;Initial Catalog=database;Integrated Security=True" in another place then the the eventtriggerd settingsLoaded method i created.. The problem is that even though the connectionstring semes to be the right, the program still connects to the "default" database that is typed in to the app.config file??

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  • Spring Weblfow 2 - Double Submit

    - by John W.
    Hello All, I am investigating a possible issue with double submits and I am looking at the possibilty of a double submit from a webflow execution. I have read many times that webflow will handle double submits, there are plenty references here. However I then came across I a forum response on the spring source forums contradicting what I read saying, SWF synchronizes on the conversation. Only one request will be processed at a time per conversation. Take note that if you're using snapshots, then it's possible repeatedly clicking on the submit button will generate a second request. I would recommend setting history to invalidate or discard in the transition from your view-state. We do have snapshots enabled but the book notes that using snapshots actually allows to solve the double submits. Does anyone have any insight on this? Thanks.

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  • Apache POI HWPF Nested Lists?

    - by Mahadevan
    Hi, I used the following code to read list structures from a word file using hwpf. My question is how to read a list structure that is nested ie a list within a list within a list and so on. if (p instanceof ListEntry) { ListEntry entry = (ListEntry) p; outText = entry.text(); outText = "<li>" + outText + "</li>"; // verifca prima e ultimo if (i > 1) { pPrev = range.getParagraph(i - 1); if (!(pPrev instanceof ListEntry)) outText = "<ul>" + outText; } if (i < nParagrafi - 1) { pNext = range.getParagraph(i + 1); if (!(pNext instanceof ListEntry)) outText = outText + "</ul>"; } if (i == nParagrafi - 1) { outText = outText + "</ul>"; }

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  • java: how to compress data into a String and uncompress data from the String

    - by Guillaume
    I want to put some compressed data into a remote repository. To put data on this repository I can only use a method that take the name of the resource and its content as a String. (like data.txt + "hello world"). The repository is moking a filesystem but is not, so I can not use File directly. I want to be able to do the following: client send to server a file 'data.txt' server compress 'data.txt' into data.zip server send to repository content of data.zip repository store data.zip client download from repository data.zip and his able to open it with its favorite zip tool I have tried a lots of compressing example found on the web but each time a send the data to the repository, my resulting zip file is corrupted. Here is a sample class, using the zip*stream and that emulate the repository showcasing my problem. The created zip file is working, but after its 'serialization' it's get corrupted. (the sample class use jakarta commons.io ) Many thanks for your help. package zip; import java.io.File; import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.IOException; import java.io.InputStream; import java.util.zip.ZipEntry; import java.util.zip.ZipInputStream; import java.util.zip.ZipOutputStream; import org.apache.commons.io.FileUtils; /** * Date: May 19, 2010 - 6:13:07 PM * * @author Guillaume AME. */ public class ZipMe { public static void addOrUpdate(File zipFile, File ... files) throws IOException { File tempFile = File.createTempFile(zipFile.getName(), null); // delete it, otherwise you cannot rename your existing zip to it. tempFile.delete(); boolean renameOk = zipFile.renameTo(tempFile); if (!renameOk) { throw new RuntimeException("could not rename the file " + zipFile.getAbsolutePath() + " to " + tempFile.getAbsolutePath()); } byte[] buf = new byte[1024]; ZipInputStream zin = new ZipInputStream(new FileInputStream(tempFile)); ZipOutputStream out = new ZipOutputStream(new FileOutputStream(zipFile)); ZipEntry entry = zin.getNextEntry(); while (entry != null) { String name = entry.getName(); boolean notInFiles = true; for (File f : files) { if (f.getName().equals(name)) { notInFiles = false; break; } } if (notInFiles) { // Add ZIP entry to output stream. out.putNextEntry(new ZipEntry(name)); // Transfer bytes from the ZIP file to the output file int len; while ((len = zin.read(buf)) > 0) { out.write(buf, 0, len); } } entry = zin.getNextEntry(); } // Close the streams zin.close(); // Compress the files if (files != null) { for (File file : files) { InputStream in = new FileInputStream(file); // Add ZIP entry to output stream. out.putNextEntry(new ZipEntry(file.getName())); // Transfer bytes from the file to the ZIP file int len; while ((len = in.read(buf)) > 0) { out.write(buf, 0, len); } // Complete the entry out.closeEntry(); in.close(); } // Complete the ZIP file } tempFile.delete(); out.close(); } public static void main(String[] args) throws IOException { final String zipArchivePath = "c:/temp/archive.zip"; final String tempFilePath = "c:/temp/data.txt"; final String resultZipFile = "c:/temp/resultingArchive.zip"; File zipArchive = new File(zipArchivePath); FileUtils.touch(zipArchive); File tempFile = new File(tempFilePath); FileUtils.writeStringToFile(tempFile, "hello world"); addOrUpdate(zipArchive, tempFile); //archive.zip exists and contains a compressed data.txt that can be read using winrar //now simulate writing of the zip into a in memory cache String archiveText = FileUtils.readFileToString(zipArchive); FileUtils.writeStringToFile(new File(resultZipFile), archiveText); //resultingArchive.zip exists, contains a compressed data.txt, but it can not //be read using winrar: CRC failed in data.txt. The file is corrupt } }

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  • Do you have any tips for comments code to keep them in step with the code?

    - by Rob Wells
    G'day, I've read both of Steve McConnell's excellent Code Complete books "Code Complete" and "Code Complete 2" and was wondering if people have any other suggestions for commenting code. My commenting mantra could be summed up by the basic idea of expressing "what the code below cannot say". While enjoying this interesting blog post by Jeff about commenting I was still left wondering "When coding, when do you feel a comment is required?" Edit: Oops. Seems to be a duplicate of this question http://stackoverflow.com/questions/121945/how-do-you-like-your-comments so sorry for the noise. Thanks to my, seemingly, SO shadow for pointing it out - wouldn't have thought I was that interesting. Now off to read the original post and see if it is relevant. Edit: I meant to emphasise the best appraoch to ensure that your comments will stay in step with the code. Maybe expressing an intent rather than the mechansim for instance.

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  • Serialization problem

    - by Falcon eyes
    Hi Every body I have a problem and want help. I have created a phonebook application and it works fine after a awhile i liked to make an upgrade for my application and i started from scratch i didn't inherit it from my old class,and i successes too ,my request "I want to migrate my contacts from the old application to the new one" ,so i made an adapter class for this reason in my new application with the following code using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.IO; using System.Windows.Forms; using System.Runtime.Serialization; using System.Runtime.Serialization.Formatters.Binary; namespace PhoneBook { class Adapter { PhoneRecord PhRecord; //the new application object CTeleRecord TelRecord; //the old application object string fileName; public Adapter(string filename) { fileName = filename; } public void convert() { PhRecord = new PhoneRecord(); TelRecord = new CTeleRecord(); FileStream OpFileSt = new FileStream(fileName, FileMode.Open,FileAccess.Read); BinaryFormatter readBin = new BinaryFormatter(); for (; ; ) { try { TelRecord.ResetTheObject(); TelRecord = (CTeleRecord)readBin.Deserialize(OpFileSt); PhRecord.SetName = TelRecord.GetName; PhRecord.SetHomeNumber = TelRecord.GetHomeNumber; PhRecord.SetMobileNumber = TelRecord.GetMobileNumber; PhRecord.SetWorkNumber = TelRecord.GetWorkNumber; PhRecord.SetSpecialNumber = TelRecord.GetSpecialNumber; PhRecord.SetEmail = TelRecord.GetEmail; PhRecord.SetNotes = TelRecord.GetNotes; PhBookContainer.phBookItems.Add(PhRecord); } catch (IOException xxx) { MessageBox.Show(xxx.Message); } catch (ArgumentException tt) { MessageBox.Show(tt.Message); } //if end of file is reached catch (SerializationException x) { MessageBox.Show(x.Message + x.Source); break; } } OpFileSt.Close(); PhBookContainer.Save(@"d:\MyPhBook.pbf"); } } } the problem is when i try to read the file ctreated by my old application i receive serialization exception with this message "Unabel to find assembly 'PhoneBook,Version=1.0.0.0,Culture=neutral,PublicK eyToken=null" and the source of exceptionis mscorlib. when i read the same file with my old application(Which is the origin of the file)i have no problem and idon't know what to do to make my adapter class work.so can somebody help please.

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  • How do I memoize expensive calculations on Django model objects?

    - by David Eyk
    I have several TextField columns on my UserProfile object which contain JSON objects. I've also defined a setter/getter property for each column which encapsulates the logic for serializing and deserializing the JSON into python datastructures. The nature of this data ensures that it will be accessed many times by view and template logic within a single Request. To save on deserialization costs, I would like to memoize the python datastructures on read, invalidating on direct write to the property or save signal from the model object. Where/How do I store the memo? I'm nervous about using instance variables, as I don't understand the magic behind how any particular UserProfile is instantiated by a query. Is __init__ safe to use, or do I need to check the existence of the memo attribute via hasattr() at each read? Here's an example of my current implementation: class UserProfile(Model): text_json = models.TextField(default=text_defaults) @property def text(self): if not hasattr(self, "text_memo"): self.text_memo = None self.text_memo = self.text_memo or simplejson.loads(self.text_json) return self.text_memo @text.setter def text(self, value=None): self.text_memo = None self.text_json = simplejson.dumps(value)

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  • How do i start with Gomoku?

    - by firstTry
    I read about Gomoku that it can be implemented using Minimax and Alpha-Beta Pruning algorithms. So, i read these algorithms and now understand how the game will be solved. But when i sat to down to code, I am facing problem how to approach it. As in , How to design the prototype functions like getNextMove or Max(Move) ? How will the next move searched? Till when should i apply the minimax algorithm. I know i can find the code online, but i want to do it myself. Can anyone please point me in the right direction?

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  • C# File.ReadAllLines not breaking on line feeds

    - by David Dickerson
    Hello, I have an application that I am building that needs to modify a configuration file. My problem is that I am not able to read the file in line by line. I keep geeting the the entire file as a single string. string ConfigTemplate = AEBuildsSPFolderName + "\Template_BuildReleaseScript.Config"; string[] fileSourceLines = File.ReadAllLines(ConfigTemplate, Encoding.Default); --Returns the entire file contents into the first array element. using (StreamReader reader = new StreamReader(ConfigTemplate)) { string line; while ((line = reader.ReadLine()) != null) --Returns the entire file contents into the first line read. Any idea of what I am doing wrong? Thanks, david

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  • Java applet - access denied to file on same web server

    - by me_here
    I've written a simple Java applet to generate a technical image based upon some data in a CSV file. I'm passing in the CSV file as a parameter to the applet: <applet code = "assaymap.AssayMapApplet" archive = "http://localhost/applet_test/AssayMap.jar" height="600px" width="800px"> <param name="csvFile" value="http://localhost/applet_test/test.csv"> </applet> As far as I understood applet security restrictions, an applet should be able to read data from the host they're on. These applets here http://www.jalview.org/examples/applets.html are using the same approach of passing in a text data file as a parameter. So I'm not sure why my own applet isn't working. The error message I get thrown is: Error with processing the CSV data. java.security.AccessControlException: access denied (java.io.FilePermission http:\localhost\applet_test\test.csv read)

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  • Is this a situation where Qt Model/View architecture is not useful?

    - by csmithmaui
    Hi, I am writing a GUI based application where I read a string of values from serial port every few seconds and I need to display most of the values in some type graphical indicator(I was thinking of QprogressBar maybe) that displays the range and the value. Some of the other data that I am parsing from the string are the date and fault codes. Also, the data is hierarchical. I wanted to use the model/view architecture of Qt because I have been interested in MVC stuff for a while but have never quite wrapped my brain around how to implement it very well. As of now, I have subclassed QAbstractItemModel and in the model I read the serial port and wrap the items parsed from the string in a Tree data structure. I can view all of the data in a QtreeView with no issues. I have also began to subclass QAbstractItemView to build my custom view with all of the Graphical Indicators and such. This is where I am getting stuck. It seems to me that in order for me to design a view that knows how to display my custom model the view needs to know exactly how all of the data in the model is organized. Doesn't that defeat the purpose of Model/View? The QTreeView I tested the model with is basically just displaying the model as it is setup in the Tree structure but I don't want to do that because the data is not all of the same type. Is the type of data or the way you would like to present it to the user a determining factor in whether or not you should use this architecture? I always assumed it was just always better to design in an MVC style. It seems to me like it might have been better to just subclass QWidget and then read in from the serial port and update all of subwidgets(graphical indicators, labels, etc...) from the subclass. Essentially, do everything in one class. Does anybody understand this issue that can explain to me either what I am missing or why I shouldn't be doing it this way. As of now I am a little confused. Thanks so much for any help!

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  • Advanced Java book in the lines of CLR via c# or C# in Depth?

    - by devoured elysium
    I want to learn about how things work in depth in Java. Coming from a c# background, there were a couple of very good books that go really deep in c# (C# in depth, CLR via c#, just to name the most popular). Is there anything like that in Java? I searched it up on amazon but nothing seemed to go that deep in Java as the two above go in c#. I don't want to know more about specific classes, or how to use this library or that other library, I want to learn how the objects are created on memory, how they get created on the stack, heap, etc. A more fundamental knowledge, let's say. I've read some chapters of Effective Java and The Java Programming Language but they don't seem to go so deep as I'd want them to go. Maybe there are other people that know both c# and Java that have read any of the referred books and know any that might be useful? Thanks

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  • Is O_NONBLOCK being set a property of the file descriptor or underlying file?

    - by Daniel Trebbien
    From what I have been reading on The Open Group website on fcntl, open, read, and write, I get the impression that whether O_NONBLOCK is set on a file descriptor, and hence whether non-blocking I/O is used with the descriptor, should be a property of that file descriptor rather than the underlying file. Being a property of the file descriptor means, for example, that if I duplicate a file descriptor or open another descriptor to the same file, then I can use blocking I/O with one and non-blocking I/O with the other. Experimenting with a FIFO, however, it appears that it is not possible to have a blocking I/O descriptor and non-blocking I/O descriptor to the FIFO simultaneously (so whether O_NONBLOCK is set is a property of the underlying file [the FIFO]): #include <errno.h> #include <fcntl.h> #include <stdio.h> #include <stdlib.h> #include <unistd.h> int main(int argc, char **argv) { int fds[2]; if (pipe(fds) == -1) { fprintf(stderr, "`pipe` failed.\n"); return EXIT_FAILURE; } int fd0_dup = dup(fds[0]); if (fd0_dup <= STDERR_FILENO) { fprintf(stderr, "Failed to duplicate the read end\n"); return EXIT_FAILURE; } if (fds[0] == fd0_dup) { fprintf(stderr, "`fds[0]` should not equal `fd0_dup`.\n"); return EXIT_FAILURE; } if ((fcntl(fds[0], F_GETFL) & O_NONBLOCK)) { fprintf(stderr, "`fds[0]` should not have `O_NONBLOCK` set.\n"); return EXIT_FAILURE; } if (fcntl(fd0_dup, F_SETFL, fcntl(fd0_dup, F_GETFL) | O_NONBLOCK) == -1) { fprintf(stderr, "Failed to set `O_NONBLOCK` on `fd0_dup`\n"); return EXIT_FAILURE; } if ((fcntl(fds[0], F_GETFL) & O_NONBLOCK)) { fprintf(stderr, "`fds[0]` should still have `O_NONBLOCK` unset.\n"); return EXIT_FAILURE; // RETURNS HERE } char buf[1]; if (read(fd0_dup, buf, 1) != -1) { fprintf(stderr, "Expected `read` on `fd0_dup` to fail immediately\n"); return EXIT_FAILURE; } else if (errno != EAGAIN) { fprintf(stderr, "Expected `errno` to be `EAGAIN`\n"); return EXIT_FAILURE; } return EXIT_SUCCESS; } This leaves me thinking: is it ever possible to have a non-blocking I/O descriptor and blocking I/O descriptor to the same file and if so, does it depend on the type of file (regular file, FIFO, block special file, character special file, socket, etc.)?

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  • Redis, it's memory limit and persistance question?

    - by Kirzilla
    Hello, I'm rather new to Redis and before using it I'd like to learn some important (as for me) details on it. So.... Redis is using RAM and HDD for storing data. RAM is used as fast read/write storage, HDD is used to make this data persistant. When Redis is started it loads all data from HDD to RAM or it loads only often queried data to the RAM? What if I have 500Mb Redis storage on HDD, but I have only 100Mb or RAM for Redis. Where can I read about it? Thank you PS: Sorry for my English

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  • Is this way of storing typed objects in memory good?

    - by Pindatjuh
    This is an "is this okay, or can it be done better" question. Topic: Storing typed objects in memory. Background information: I'm building a compiler for the x86-32 platform for my language. My goal includes typed objects. Idea: Every primitive is a semi-class (it can be used as if it was a normal class, but it's stored more compact). Every class is represented by primitives and some meta-data (containing class-properties, inheritance stuff, etc.). The meta-data is complex: it doesn't use fields but instead context-switches. For primitives, the meta-data is very small, compared to a "real" class, which is alot bigger. This enables another idea that "primitives are objects", in my language, which I found nessecairy. Example: If I have an array of 32 booleans, then the pure content of this array is exactly 4 byte (32 bits of booleans). The meta-data will contain flags that the type is an array of booleans, which contains 32 entries. The meta-data is very compacted, on bit-level: using a sort of "packing" mechanism, which is read by a FSM at runtime, when doing inspection of the type (like when passing the object to methods for checking, etc.) For instance (read from left to right, top to bottom, remember vertical possition when going to the right, and check nearest column header for meaning of switch): Primitive? Array? Type-Meta 1 Byte? || Size (1 byte) 1 1 [...] 1 [...] done 0 2 Bytes? || Size (2 bytes) 1 [...] done || Size (4 bytes) 0 [...] done Integer? 1 Byte? 2 Bytes? 0 1 0 1 done 1 done 0 done Boolean? Byte? 0 1 0 done 1 done More-Primitives 0 .... Class-Stuff (Huge) 0 ... (After reaching done the data is inserted. || = byte alignement. [...] is variable sized. ... is not described here, for simplicity. And let's call them cost-based-data-structures.) For an array of 32 booleans containing all true values, the memory for this type would be (read top-down): 1 Primitive 1 Array 1 ArrayType: Primitive 0 Not-Array 0 Not-Integer 1 Boolean 0 Not-Byte (thus bit) 1 Integer Size: 1 Byte 00100000 Array size 11111111 11111111 11111111 11111111 Data Thus, 8 bytes represent 32 booleans in an array: 11100101 00100000 11111111 11111111 11111111 11111111 Is this okay, or can it be done better?

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