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  • gdi+ removable device IO Safe problem

    - by sxingfeng
    I am using gdi+ for image format checking. It is really surprising that gdi+ Image img(path); does not throw exception when a device is removed. for example, I am checking a list of image files on a removable device. I plug the disk off, Then My Application will crashed. How can I avoid such problem? Many Thanks! I am using c++ gdi+ windows ,many thanks.

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  • Python file-io code listing current folder path instead of the specified

    - by Tom Brito
    I have the code: import os import sys fileList = os.listdir(sys.argv[1]) for file in fileList: if os.path.isfile(file): print "File >> " + os.path.abspath(file) else: print "Dir >> " + os.path.abspath(file) Located in my music folder ("/home/tom/Music") When I call it with: python test.py "/tmp" I expected it to list my "/tmp" files and folders with the full path. But it printed lines like: Dir >> /home/tom/Music/seahorse-gw2jNn Dir >> /home/tom/Music/FlashXX9kV847 Dir >> /home/tom/Music/pulse-DcIEoxW5h2gz This is, the correct file names, but the wrong path (and this files are not either in my Music folder).. What's wrong with this code?

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  • IO operation taking long time for files in remote server

    - by user841311
    I have files of size 150 MB each in a remote server in a different domain in the network. I am accessing them thorugh UNC path. I want to read the file content and perform a basic string search. When I try reading the files line by line, the operation just don't finish and takes long time, more than 30 minutes. However when I copy those files to my local machine, the same code reads and performs the string search in less than 5 seconds. I don't have .NET framework installed in the server so I have to do this from my machine. I want to perform all this through C# code in .NET framework 3.5 so I don't want to explictly ftp all the files to my machine before performing this operation. Sample Code DirectoryInfo dir = new DirectoryInfo(@strFilePath); FileInfo[] fiArray = dir.getFiles("*.txt"); foreach (FileInfo fi in fiArray) { //reading file content from server takes long time but fast in local machine //perform string search } Let me know if my requirement is not clear. Thanks in advance!

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  • Ruby : UTF-8 IO

    - by subtenante
    I use ruby 1.8.7. I try to parse some text files containing greek sentences, encoded in UTF-8. (I can't much paste here sample files, because they are subject to copyright. Really just some greek text encoded in UTF-8.) I want, for each file, to parse the file, extract all the words, and make a list of each new word found in this file. All that saved to one big index file. Here is my code : #!/usr/bin/ruby -KU def prepare_line(l) l.gsub(/^\s*[ST]\d+\s*:\s*|\s+$|\(\d+\)\s*/u, "") end def tokenize(l) l.split /['·.;!:\s]+/u end $dict = {} $cpt = 0 $out = File.new 'out.txt', 'w' def lesson(file) $cpt = $cpt + 1 file.readlines.each do |l| $out.puts l l = prepare_line l tokenize(l).each do |t| unless $dict[t] $dict[t] = $cpt $out.puts " #{t}\n" end end end end Dir.new('etc/').each do |filename| f = File.new("etc/#{filename}") unless File.directory? f lesson f end end Here is part of my output : ?@???†?†?????????? ?...[snip very long hangul/hanzi mishmash]... ????????†? ???N2 : ?e?te?? (2) µ???µa (Note that the puts l part seems to work fine, at the end of the given output line.) Any idea what is wrong with my code ? (General comments about ruby idioms I could use are very welcome, I'm really a beginner.)

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  • Java io ugly try-finally block

    - by Tom Brito
    Is there a not so ugly way of treat the close() exception to close both streams then: InputStream in = new FileInputStream(inputFileName); OutputStream out = new FileOutputStream(outputFileName); try { copy(in, out); } finally { try { in.close(); } catch (Exception e) { try { // event if in.close fails, need to close the out out.close(); } catch (Exception e2) {} throw e; // and throw the 'in' exception } out.close(); }

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  • Disk IO Performance Limitations based on numbers of folders/files

    - by Josh
    I have an application where users are allowed to upload images to the server. Our Web Server is a windows 2008 server and we have a site (images.mysite.com) that points to a shared drive on a unix box. The code used to do the uploading is C# 3.5. The system currently supports a workflow where after a threshold is met a new subfolder can be generated. The question we have is how many files and/or subfolders can you have in a single folder before there is a degredation in performance - in serving the images up through IIS 7 and reading/writing through code?

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  • Network IO using Credentials

    - by John
    Is it possible to move files from a network location that requires credentials to another network location that also requires credentials without mapping any drive. (ie: Without any use of P/Invoke) Example: FileInfo fi = new FileInfo(@"\\SomeComputer\SomeDrive\SomeFolder\someFile.txt"); fi.MoveTo(@"\\AnotherComputer\AnotherDrive\AnotherFolder\AnotherFile.txt"); This works fine if the source and destination network drives are already mapped but if they are not It doesn't.

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  • CMT Blog: Virtual IO gets better for LDoms

    - by uwes
    As we all know virtual IO is of great use in the IT environments of today but when it comes to performance we often have to pay the price. In his Blog entry Improved vDisk Performance for Ldoms, Stefan Hinker explained how the new implementation of the vdisk/vds software stack in Solaris 11.1 SRU 19 (and a Solaris 10 patch sortly afterwards) significantly improves latency and throughput of the vitual disk IO.

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  • How to unit test with lots of IO

    - by Eric
    I write Linux embedded software which closely integrates with hardware. My modules are such as : -CMOS video input with kernel driver (v4l2) -Hardware h264/mpeg4 encoders (texas instuments) -Audio Capture/Playback (alsa) -Network IO I'd like to have automated testing for those functionalities, such as integration testing. I am not sure how I can automate this process since most of the top level functionalities I face are IO bound. Sure, it is easy to test functions individually, but whole process checking means depending on tons of external dependencies only available at runtime.

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  • Should I learn Haskell or F# if I already know OCaml?

    - by Unknown
    I am wondering if I should continue to learn OCaml or switch to F# or Haskell. Here are the criteria I am most interested in: Longevity Which language will last longer? I don't want to learn something that might be abandoned in a couple years by users and developers. Will Inria, Microsoft, University of Glasgow continue to support their respective compilers for the long run? Practicality Articles like this make me afraid to use Haskell. A hash table is the best structure for fast retrieval. Haskell proponents in there suggest using Data.Map which is a binary tree. I don't like being tied to a bulky .NET framework unless the benefits are large. I want to be able to develop more than just parsers and math programs. Well Designed I like my languages to be consistent. Please support your opinion with logical arguments and citations from articles. Thank you.

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  • Vista seems to prevent .net from reading/updating file attributes.

    - by CFP
    Hello everyone! The following function copies a file from Source & Path to Dest & Path, normally setting file attributes to normal before copying. Yet, a user of my app has reported it to fail when copying readonly files, returning a permissions-related error. The user is however running the code as administrator, and the error happens - quite strangely - on the SetLastWriteTimeUtc line. Although the code reports that the file attributes are set to normal, windows explorer shows that they are set to read only. Sub CopyFile(ByVal Path As String, ByVal Source As String, ByVal Dest As String) If IO.File.Exists(Dest & Path) Then IO.File.SetAttributes(Dest & Path, IO.FileAttributes.Normal) IO.File.Copy(Source & Path, Dest & Path, True) If Handler.GetSetting(ConfigOptions.TimeOffset, "0") <> "0" Then IO.File.SetAttributes(Dest & Path, IO.FileAttributes.Normal) IO.File.SetLastWriteTimeUtc(Dest & Path, IO.File.GetLastWriteTimeUtc(Dest & Path).AddHours(Handler.GetSetting(ConfigOptions.TimeOffset, "0"))) End If IO.File.SetAttributes(Dest & Path, IO.File.GetAttributes(Source & Path)) End Sub I just fail to see the problem in this code, so after long hours of searching for the solution, I thought one of SO VB.Net Gurus might help :) Thanks a lot. Edit: The actual error is Access to the path '(..)' is denied. at System.IO.__Error.WinIOError(Int32 errorCode, String maybeFullPath) at System.IO.FileStream.Init(String path, FileMode mode, FileAccess access, Int32 rights, Boolean useRights, FileShare share, Int32 bufferSize, FileOptions options, SECURITY_ATTRIBUTES secAttrs, String msgPath, Boolean bFromProxy) at System.IO.FileStream..ctor(String path, FileMode mode, FileAccess access, FileShare share, Int32 bufferSize) at System.IO.File.OpenFile(String path, FileAccess access, SafeFileHandle& handle) at System.IO.File.SetLastWriteTimeUtc(String path, DateTime lastWriteTimeUtc)

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  • Create My own language with "Functional Programming Language"

    - by esehara
    I prefer Haskell. I already know How to create my own language with Procedural Language (for example: C, Java, Python, etc). But, I know How to create my own language with Functional Language (for example Haskell, Clojure and Scala). I've already read: Internet Resources Write Yourself a Scheme in 48 Hours Real World Haskell - Chapter 16.Using Persec Writing A Lisp Interpreter In Haskell Parsec, a fast combinator parser Implementing functional languages: a tutorial Books Introduction Functional Programming Using Haskell 2nd Edition -- Haskell StackOverflow (but with procedural language) Learning to write a compiler create my own programming language Source Libraries and tools/HJS -- Haskell Are there any other good sources? I wants to get more links,or sources.

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  • Make error when compiling Perl 5.12.1 (RHEL 5.5)

    - by ascent1729
    I am trying to compile Perl 5.12.1 in my home directory on Red Hat Enterprise Linux 5.5. However, when I try to make, I eventually receive the following error: Making IO (all) make[1]: Entering directory `/users/rmi1/build/perl-5.12.0/dist/IO' make[1]: Leaving directory `/users/rmi1/build/perl-5.12.0/dist/IO' Making all in dist/IO make all PERL_CORE=1 LIBPERL_A=libperl.a LINKTYPE=dynamic make[1]: Entering directory `/users/rmi1/build/perl-5.12.0/dist/IO' cc -c -fno-strict-aliasing -pipe -fstack-protector -I/usr/local/include -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64 -O2 -DVERSION=\"1.25_02\" -DXS_VERSION=\"1.25_02\" -fPIC "-I../.." IO.c IO.xs: In function ‘XS_IO__Poll__poll’: IO.xs:249: error: invalid application of ‘sizeof’ to incomplete type ‘struct pollfd’ IO.xs:253: error: invalid use of undefined type ‘struct pollfd’ IO.xs:253: error: dereferencing pointer to incomplete type IO.xs:255: error: invalid use of undefined type ‘struct pollfd’ IO.xs:255: error: dereferencing pointer to incomplete type IO.xs:257: error: invalid use of undefined type ‘struct pollfd’ IO.xs:257: error: dereferencing pointer to incomplete type IO.xs:261: error: invalid use of undefined type ‘struct pollfd’ IO.xs:261: error: dereferencing pointer to incomplete type IO.xs:262: error: invalid use of undefined type ‘struct pollfd’ IO.xs:262: error: dereferencing pointer to incomplete type make[1]: *** [IO.o] Error 1 make[1]: Leaving directory `/users/rmi1/build/perl-5.12.0/dist/IO' Unsuccessful make(dist/IO): code=512 at make_ext.pl line 449. make: *** [lib/auto/IO/IO.so] Error 2 What could be causing this?

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  • How do I organize a GUI application for passing around events and for setting up reads from a shared resource

    - by Savanni D'Gerinel
    My tools involved here are GTK and Haskell. My questions are probably pretty trivial for anyone who has done significant GUI work, but I've been off in the equivalent of CGI applications for my whole career. I'm building an application that displays tabular data, displays the same data in a graph form, and has an edit field for both entering new data and for editing existing data. After asking about sharing resources, I decided that all of the data involved will be stored in an MVar so that every component can just read the current state from the MVar. All of that works, but now it is time for me to rearrange the application so that it can be interactive. With that in mind, I have three widgets: a TextView (for editing), a TreeView (for displaying the data), and a DrawingArea (for displaying the data as a graph). I THINK I need to do two things, and the core of my question is, are these the right things, or is there a better way. Thing the first: All event handlers, those functions that will be called any time a redisplay is needed, need to be written at a high level and then passed into the function that actually constructs the widget to begin with. For instance: drawStatData :: DrawingArea -> MVar Core.ST -> (Core.ST -> SetRepWorkout.WorkoutStore) -> IO () createStatView :: (DrawingArea -> IO ()) -> IO VBox createUI :: MVar Core.ST -> (Core.ST -> SetRepWorkout.WorkoutStore) -> IO HBox createUI storeMVar field = do graphs <- createStatView (\area -> drawStatData area storeMVar field) hbox <- hBoxNew False 10 boxPackStart hbox graphs PackNatural 0 return hbox In this case, createStatView builds up a VBox that contains a DrawingArea to graph the data and potentially other widgets. It attaches drawStatData to the realize and exposeEvent events for the DrawingArea. I would do something similar for the TreeView, but I am not completely sure what since I have not yet done it and what I am thinking of would involve replacing the TreeModel every time the TreeView needs to be updated. My alternative to the above would be... drawStatData :: DrawingArea -> MVar Core.ST -> (Core.ST -> SetRepWorkout.WorkoutStore) -> IO () createStatView :: IO (VBox, DrawingArea) ... but in this case, I would arrange createUI like so: createUI :: MVar Core.ST -> (Core.ST -> SetRepWorkout.WorkoutStore) -> IO HBox createUI storeMVar field = do (graphbox, graph) <- createStatView (\area -> drawStatData area storeMVar field) hbox <- hBoxNew False 10 boxPackStart hbox graphs PackNatural 0 on graph realize (drawStatData graph storeMVar field) on graph exposeEvent (do liftIO $ drawStatData graph storeMVar field return ()) return hbox I'm not sure which is better, but that does lead me to... Thing the second: it will be necessary for me to rig up an event system so that various events can send signals all the way to my widgets. I'm going to need a mediator of some kind to pass events around and to translate application-semantic events to the actual events that my widgets respond to. Is it better for me to pass my addressable widgets up the call stack to the level where the mediator lives, or to pass the mediator down the call stack and have the widgets register directly with it? So, in summary, my two questions: 1) pass widgets up the call stack to a global mediator, or pass the global mediator down and have the widgets register themselves to it? 2) pass my redraw functions to the builders and have the builders attach the redraw functions to the constructed widgets, or pass the constructed widgets back and have a higher level attach the redraw functions (and potentially link some widgets together)? Okay, and... 3) Books or wikis about GUI application architecture, preferably coherent architectures where people aren't arguing about minute details? The application in its current form (displays data but does not write data or allow for much interaction) is available at https://bitbucket.org/savannidgerinel/fitness . You can run the application by going to the root directory and typing runhaskell -isrc src/Main.hs data/ or... cabal build dist/build/fitness/fitness data/ You may need to install libraries, but cabal should tell you which ones.

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  • How do I code a tree of objects in Haskell with pointers to parent and children?

    - by axilmar
    I've got the following problem: I have a tree of objects of different classes where an action in the child class invalidates the parent. In imperative languages, it is trivial to do. For example, in Java: public class A { private List<B> m_children = new LinkedList<B>(); private boolean m_valid = true; public void invalidate() { m_valid = false; } public void addChild(B child) { m_children.add(child); child.m_parent = this; } } public class B { public A m_parent = null; private int m_data = 0; public void setData(int data) { m_data = 0; m_parent.invalidate(); } } public class Main { public static void main(String[] args) { A a = new A(); B b = new B(); b.setData(0); //invalidates A } } How do I do the above in Haskell? I cannot wrap my mind around this, since once I construct an object in Haskell, it cannot be changed. I would be much obliged if the relevant Haskell code is posted.

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  • SQL SERVER – Pending IO request in SQL Server – DMV

    - by pinaldave
    I received following question: “How do we know how many pending IO requests are there for database files (.mdf, .ldf) individually?” Very interesting question and indeed answer is very interesting as well. Here is the quick script which I use to find the same. It has to be run in the context of the database for which you want to know pending IO statistics. USE DATABASE GO SELECT vfs.database_id, df.name, df.physical_name ,vfs.FILE_ID, ior.io_pending FROM sys.dm_io_pending_io_requests ior INNER JOIN sys.dm_io_virtual_file_stats (DB_ID(), NULL) vfs ON (vfs.file_handle = ior.io_handle) INNER JOIN sys.database_files df ON (df.FILE_ID = vfs.FILE_ID) I keep this script handy as it works like magic every time. If you use any other script please post here and I will post it with due credit. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: PostADay, SQL, SQL Authority, SQL DMV, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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  • SQLBits - Fusion IO and Attunity confirmed as exhibitors

    - by simonsabin
    We are very excited that Attunity are going to be exhibiting at SQLBits VI, they must have a great product because any client I see that is integrating SQL with other stores such as DB2 and Oracle seem to be using Attunity's providers. On top of that we have a new exhibitor. Fusion IO will be coming along and I hope will be bringing some amazing demos of their kit. SSD storage is the future and Fusion IO are at the top of the game. Many in the SQL community have said that SSD for tempdb is just awesome, come and have a chat with the guys to talk about your high performance storage needs.

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  • SQLBits - Fusion IO and Attunity confirmed as exhibitors

    - by simonsabin
    We are very excited that Attunity are going to be exhibiting at SQLBits VI, they must have a great product because any client I see that is integrating SQL with other stores such as DB2 and Oracle seem to be using Attunity's providers. On top of that we have a new exhibitor. Fusion IO will be coming along and I hope will be bringing some amazing demos of their kit. SSD storage is the future and Fusion IO are at the top of the game. Many in the SQL community have said that SSD for tempdb is just awesome, come and have a chat with the guys to talk about your high performance storage needs.

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  • Misconceptions about purely functional languages?

    - by Giorgio
    I often encounter the following statements / arguments: Pure functional programming languages do not allow side effects (and are therefore of little use in practice because any useful program does have side effects, e.g. when it interacts with the external world). Pure functional programming languages do not allow to write a program that maintains state (which makes programming very awkward because in many application you do need state). I am not an expert in functional languages but here is what I have understood about these topics until now. Regarding point 1, you can interact with the environment in purely functional languages but you have to explicitly mark the code (functions) that introduces them (e.g. in Haskell by means of monadic types). Also, AFAIK computing by side effects (destructively updating data) should also be possible (using monadic types?) but is not the preferred way of working. Regarding point 2, AFAIK you can represent state by threading values through several computation steps (in Haskell, again, using monadic types) but I have no practical experience doing this and my understanding is rather vague. So, are the two statements above correct in any sense or are they just misconceptions about purely functional languages? If they are misconceptions, how did they come about? Could you write a (possibly small) code snippet illustrating the Haskell idiomatic way to (1) implement side effects and (2) implement a computation with state?

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  • What's the proper term for a function inverse to a constructor? Deconstructor, destructor, or something else?

    - by Petr Pudlák
    Edit: I'm rephrasing the question a bit. Apparently I caused some confusion because I didn't realize that the term destructor is used in OOP for something quite different - it's a function invoked when an object is being destroyed. In functional programming we (try to) avoid mutable state so there is no such equivalent to it. (I added the proper tag to the question.) Instead, I've seen that the record field for unwrapping a value (especially for single-valued data types such as newtypes) is sometimes called destructor or perhaps deconstructor. For example, let's have (in Haskell): newtype Wrap = Wrap { unwrap :: Int } Here Wrap is the constructor and unwrap is what? I've seen both, for example: ... Most often, one supplies smart constructors and destructors for these to ease working with them. ... at Haskell wiki, or ... The general theme here is to fuse constructor - deconstructor pairs like ... at Haskell wikibook (here it's probably meant in a bit more general sense). The questions are: How do we call unwrap in functional programming? Deconstructor? Destructor? Or by some other term? And to clarify, is this terminology applicable to other functional languages, or is it used just in the Has

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