Search Results

Search found 6115 results on 245 pages for 'michael 19'.

Page 27/245 | < Previous Page | 23 24 25 26 27 28 29 30 31 32 33 34  | Next Page >

  • Apache config file. Redirect permanent gives 403 error

    - by Homunculus Reticulli
    I am changing my domain from foo.com to foobar.org. I used a Redirect permanent in my apache config file, and then restarted apache. When I try to access the old domain foo.com, I get a 403 error. This is what my apache config file looks like: <VirtualHost *:80> ServerName foo.com #ServerAlias www.foo.com #ServerAdmin [email protected] Redirect permanent / http://www.foobar.org/ DocumentRoot /path/to/project/foo/web DirectoryIndex index.php # CustomLog with format nickname LogFormat "%h %l %u %t \"%r\" %>s %b" common CustomLog "|/usr/bin/cronolog /var/log/apache2/%Y%m.foo.access.log" common LogLevel notice ErrorLog "|/usr/bin/cronolog /var/log/apache2/%Y%m.foo.errors.log" <Directory /> Order Deny,Allow Deny from all </Directory> <Files ~ "^\.ht"> Order allow,deny Deny from all </Files> <Directory /path/to/project/foo/web> Options -Indexes -Includes AllowOverride All Allow from All RewriteEngine On # We check if the .html version is here (cacheing) RewriteRule ^$ index.html [QSA] RewriteRule ^([^.])$ $1.html [QSA] RewriteCond %{REQUEST_FILENAME} !-f # No, so we redirect to our front end controller RewriteRule ^(.*)$ index.php [QSA,L] </Directory> <Directory /path/to/project/foo/web/uploads> Options -ExecCGI -FollowSymLinks -Indexes -Includes AllowOverride None php_flag engine off </Directory> Alias /sf /lib/vendor/symfony/symfony-1.3.8/data/web/sf <Directory /lib/vendor/symfony/symfony-1.3.8/data/web/sf> # Alias /sf /lib/vendor/symfony/symfony-1.4.19/data/web/sf # <Directory /lib/vendor/symfony/symfony-1.4.19/data/web/sf> Options -Indexes -Includes AllowOverride All Allow from All </Directory> </VirtualHost> Can anyone spot what I may be doing wrong?. The site foobar.org does exist so I don't know why this error occurs - help?

    Read the article

  • Flash removal and installation issue

    - by Theo
    I'm having this issue trying to uninstall and/or upgrade the Adobe flash player plug-in. Here's what I've ran through the terminal: $ sudo apt-get install -f Reading package lists... Done Building dependency tree Reading state information... Done Correcting dependencies... Done The following packages were automatically installed and are no longer required: linux-headers-3.0.0-13-generic libgladeui-1-11 linux-headers-3.0.0-19-generic linux-headers-3.0.0-13 linux-headers-3.0.0-19 erlang-base Use 'apt-get autoremove' to remove them. The following packages will be REMOVED: adobe-flashplugin 0 upgraded, 0 newly installed, 1 to remove and 2 not upgraded. 1 not fully installed or removed. After this operation, 10.2 MB disk space will be freed. Do you want to continue [Y/n]? y (Reading database ... 375840 files and directories currently installed.) Removing adobe-flashplugin ... update-alternatives: error: no alternatives for iceape-flashplugin. update-alternatives: error: no alternatives for iceape-flashplugin. dpkg: error processing adobe-flashplugin (--remove): subprocess installed pre-removal script returned error exit status 2 No apport report written because MaxReports is reached already postinst called with argument `abort-remove' dpkg: error while cleaning up: subprocess installed post-installation script returned error exit status 1 Errors were encountered while processing: adobe-flashplugin E: Sub-process /usr/bin/dpkg returned an error code (1) Please advise if you can. Let me know if there is any other info you need.

    Read the article

  • Slow dvd burning/reading speeds: how to solve

    - by wouter205
    I have a problem on which I'm struggling since i started using linux a year ago on my desktop, but still haven't found a solution for it. When reading or burning a dvd, the speeds are very slow (mostly under 1x) whilst I did selected the fastest speed in k3b. As such, it takes up to 40-50 minutes to burn one dvd! I read about enabling dma this post but it didn't help. This is the output for dmesg | grep -i dma > [ 0.000000] DMA 0x00000010 -> 0x00001000 [ 0.000000] DMA32 0x00001000 -> 0x00100000 [ 0.000000] DMA zone: 56 pages used for memmap [ 0.000000] DMA zone: 5 pages reserved [ 0.000000] DMA zone: 3921 pages, LIFO batch:0 [ 0.000000] DMA32 zone: 3527 pages used for memmap [ 0.000000] DMA32 zone: 254441 pages, LIFO batch:31 [ 0.000000] Policy zone: DMA32 [ 0.120356] pnp 00:01: [dma 4] [ 0.120968] pnp 00:05: [dma 2] [ 0.121421] pnp 00:06: [dma 3] [ 0.122617] pnp 00:0b: [dma 0 disabled] [ 0.852321] ata1: SATA max UDMA/133 cmd 0xec00 ctl 0xe480 bmdma 0xe000 irq 19 [ 0.852325] ata2: SATA max UDMA/133 cmd 0xe400 ctl 0xe080 bmdma 0xe008 irq 19 [ 0.861633] ata3: PATA max UDMA/133 cmd 0x1f0 ctl 0x3f6 bmdma 0xff00 irq 14 [ 0.861636] ata4: PATA max UDMA/133 cmd 0x170 ctl 0x376 bmdma 0xff08 irq 15 [ 1.329411] ata1.00: ATA-7: Maxtor 6V250F0, VA111630, max UDMA/133 [ 1.345418] ata1.00: configured for UDMA/133 [ 1.820606] ata4.00: ATAPI: PHILIPS DVDR1660P1, P1.3, max UDMA/33 [ 1.820610] ata4.00: WARNING: ATAPI DMA disabled for reliability issues. It can be enabled [ 1.820613] ata4.00: WARNING: via pata_ali.atapi_dma modparam or corresponding sysfs node. [ 1.836681] ata4.00: configured for UDMA/33 [ 12.296600] parport0: PC-style at 0x378 (0x778), irq 7, dma 3 [PCSPP,TRISTATE,COMPAT,EPP,ECP,DMA] reading the third and fourth last line, I assume there is indeed a problem with dma? edit: this question still is not solved. Could anyone come up with an other solution please? Thanks

    Read the article

  • CodePlex Daily Summary for Tuesday, July 23, 2013

    CodePlex Daily Summary for Tuesday, July 23, 2013Popular ReleasesHome Access Plus+: v9.3: UPDATED RELEASE Fixed: Issue with enabling LDAP encryption Added: Encrypted/Signed LDAP Queries Fixed: Wrong Modernizr reference on the setup page Changed: Code on the AD Tree Picker Upgraded: Dynatree Fixed: Removed Dynatree Debug Data Added: Time bar for the current day Added: Code to block booking/removing of bookings after the lesson time has past Fixed: New sidebar position issue Added: Decode for the NotesMagelia WebStore Open-source Ecommerce software: Magelia WebStore 2.4: Magelia WebStore version 2.4 introduces new and improved features: Basket and order calculation have been redesigned with a more modular approach geographic zone algorithms for tax and shipping calculations have been re-developed. The Store service has been split in three services (store, basket, order). Product start and end dates have been added. For variant products a unique code has been introduced for the top (variable) product, product attributes can now be defined at the top ...GoAgent GUI: GoAgent GUI 1.3.0 Beta: ??????????: Windows XP SP3 Windows Vista SP1 Windows 7 Windows 8 Windows 8.1 ??Windows 8.1???????????? ????: .Net Framework 4.0 http://59.111.20.19/download/17718/33240761/4/exe/69/54/17718_1/dotNetFx40_Full_x86_x64.exe Microsoft Visual C++ 2010 Redistributable Package http://59.111.20.23/download/4894298/8555584/1/exe/28/176/1348305610524_944/vcredist_x86.exe ???????????????。 ?????????????,??????????,??????????????(????) ?????Windows XP?Windows 7????,???????????,?issue??????。uygw@outlook.comLINQ to Twitter: LINQ to Twitter v2.1.08: Supports .NET 3.5, .NET 4.0, .NET 4.5, Silverlight 4.0, Windows Phone 7.1, Windows Phone 8, Client Profile, Windows 8, and Windows Azure. 100% Twitter API coverage. Also supports Twitter API v1.1! Also on NuGet.AndroidCopyAndPaste: Capood: Erstes Release für Evaluation --> Changeset 26675fastJSON: v2.0.17: 2.0.17 - added serialization of static fields and properties - added dynamic object support and testKartris E-commerce: Kartris v2.5002: This is the release version of Kartris with the responsive interface based on Zurb's Foundation framework. It will work on any screen size, down to and including mobile devices such as the iphone. We've also fixed issues with Apple iOS products being treated by ASP.NET as 'downscale' devices, which broke some functionality in Kartris. This release also includes native Bitcoin support (no third party services required - it communicates directly with the standard Bitcoin client via a JSON API)...VG-Ripper & PG-Ripper: PG-Ripper 1.4.15: changes NEW: Added Support for "ImgChili.net" links NEW: Added Support for "ImgBabes.com" linksAcDown?????: AcDown????? v4.4.3: ??●AcDown??????????、??、??、???????。????,????,?????????????????????????。???????????Acfun、????(Bilibili)、??、??、YouTube、??、???、??????、SF????、????????????。 ●??????AcPlay?????,??????、????????????????。 ● AcDown???????C#??,????.NET Framework 2.0??。?????"Acfun?????"。 ??v4.4.3 ?? ??Bilibili????????????? ???????????? ????32??64? Windows XP/Vista/7/8 ???? 32??64? ???Linux ????(1)????????Windows XP???,????????.NET Framework 2.0???(x86),?????"?????????"??? (2)???????????Linux???,????????Mono?? ??2.10?...Magick.NET: Magick.NET 6.8.6.601: Magick.NET linked with ImageMagick 6.8.6.6. These zip files are also available as a NuGet package: https://nuget.org/profiles/dlemstra/C# Intellisense for Notepad++: Initial release: Members auto-complete Integration with native Notepad++ Auto-Completion Auto "open bracket" for methods Right-arrow to accept suggestions51Degrees.mobi - Mobile Device Detection and Redirection: 2.1.19.4: One Click Install from NuGet This release introduces the 51Degrees.mobi IIS Vary Header Fix. When Compression and Caching is used in IIS, the Vary header is overwritten, making intelligent caching with dynamic content impossible. Find out more about installing the Vary Header fix. Changes to Version 2.1.19.4Handlers now have a ‘Count’ property. This is an integer value that shows how many devices in the dataset that use that handler. Provider.cs -> GetDeviceInfoByID to address a problem w...Centrify DirectControl PowerShell Module: 1.5.709: -fix- Computer password is correctly set when preparing Computer account for Self-Service join and hostname is longer than 14 charsDLog: DLog v1.0: Log v1.0SalarDbCodeGenerator: SalarDbCodeGenerator v2.1.2013.0719: Version 2.1.2013.0719 2013/7/19 Pattern Changes: * DapperContext pattern is added. * All patterns are updated to work with one-to-one relations. Changes: * One-to-one relation is supported. * Minor bug fixes.Player Framework by Microsoft: Player Framework for Windows and WP (v1.3 beta 2): Includes all changes in v1.3 beta 1 Additional support for Windows 8.1 Preview New API (JS): addTextTrack New API (JS): msKeys New API (JS): msPlayToPreferredSourceUri New API (JS): msSetMediaKeys New API (JS): onmsneedkey New API (Xaml): SetMediaStreamSource method New API (Xaml): Stretch property New API (Xaml): StretchChanged event New API (Xaml): AreTransportControlsEnabled property New API (Xaml): IsFullWindow property New API (Xaml): PlayToPreferredSourceUri proper...Outlook 2013 Add-In: Multiple Calendars: As per popular request, this new version includes: - Support for multiple calendars. This can be enabled in the configuration by choosing which ones to show/hide appointments from. In some cases (public folders) it may time out and crash, and so far it only supports "My Calendars", so not shared ones yet. Also they're currently shown in the same font/color so there are no confusions with color categories, but please drop me a line on any suggestions you'd like to see implemented. - Added fri...Circuit Diagram: Circuit Diagram 2.0 Beta 2: New in this release: Show grid in editor Cut/copy/paste support Bug fixesOrchard Project: Orchard 1.7 RC: Planning releasedTerminals: Version 3.1 - Release: Changes since version 3.0:15992 Unified usage of icons in user interface Added context menu in Organize favorites grid Fixed:34219 34210 34223 33981 34209 Install notes:No changes in database (use database from release 3.0) No upgrade of configuration, passwords, credentials or favorites See also upgrade notes for release 3.0New ProjectsAerCloud.net FaceTools Client - Python, Linux & Windows: This project source code provides a step by step guide for using AerCloud.net Framework as a Service API. For more information please visit http://www.aercloudCode Snippet Manager: It is a simple Code Snippet Manager.. that I use when presenting tutorials. Features: - Insert a code snippet from the clipboard into program - Delete code sniDeutschWortSammler: A tiny English-German dictionary.DNN Testimonials: Virtual Essentials is a custom software development company. We strive to put joy back into the lives of people by removing the pain points through technologyDXWTEC: legsGoldenDream TeamWork: CourseWork for DB Course in Telerik Academy. Kpaint: Our work with Kpaint has proven to have provide highly accurate results mostly with the exception of occasion jittery of the paint brush. The voice recognition LAura: LAura checks the presence status of the currently signed in User and colorizes the Windows Window Color.MAPIFolders: MAPIFolders is intended as a successor to PFDAVAdmin and ExFolders.Microsoft Lab of Things Analytics: This is a project by students at University College London. We are creating analytics that will add value to home automation leveraging Microsoft Lab of Things.MySitelongdream: My siteMyTestSolution: this is a solution used just for laboratory purposeOrchestrator EventLog Integration Pack: Orchestrator Integration Pack to write spezific events in any Event Log.Planter's Supermarket: sdfResize images before upload: It will resize all images in folder recursively and store them in a store accountsampletranscodeffmpeg: a project for transcode for joyseeSCSM Perf Test Harness: Source Code for Travis Wright's LoadGen Tool for Service Manager. Simple Compression: Simple Compression is a .Net library that provides compression methods for use in an application.The Memory Game: This was my first WPF application.What day of the week is your birthday?: A program that can find the day of the week you were born!!!!!Windows Recovery Software: Recover Data Software for windows helps you to recover all type of data which has been lost due to several reasons.Xjs: Javascript framework to allow faster web development on the browser side

    Read the article

  • Building Publishing Pages in Code

    - by David Jacobus
    Originally posted on: http://geekswithblogs.net/djacobus/archive/2013/10/27/154478.aspxOne of the Mantras we developers try to follow: Ensure that the solution package we deliver to the client is complete.  We build Web Parts, Master Pages, Images, CSS files and other artifacts that we push to the client with a WSP (Solution Package) And then we have them finish the solution by building their site pages by adding the web parts to the site pages.       I am a proponent that we,  the developers,  should minimize this time consuming work and build these site pages in code.  I found a few blogs and some MSDN documentation but not really a complete solution that has all these artifacts working in one solution.   What I am will discuss and provide a solution for is a package that has: 1.  Master Page 2.  Page Layout 3.  Page Web Parts 4.  Site Pages   Most all done in code without the development team or the developers having to finish up the site building process spending a few hours or days completing the site!  I am not implying that in Development we do this. In fact,  we build these pages incrementally testing our web parts, etc. I am saying that the final action in our solution is that we take all these artifacts and add them to the site pages in code, the client then only needs to activate a few features and VIOLA their site appears!.  I had a project that had me build 8 pages like this as part of the solution.   In this blog post, I am taking a master page solution that I have called DJGreenMaster.  On My Office 365 Development Site it looks like this:     It is a generic master page for a SharePoint 2010 site Along with a three column layout.  Centered with a footer that uses a SharePoint List and Web Part for the footer links.  I use this master page a lot in my site development!  Easy to change the color and site logo with a little CSS.   I am going to add a few web parts for discussion purposes and then add these web parts to a site page in code.    Lets look at the solution package for DJ Green Master as that will be the basis project for building the site pages:   What you are seeing  is a complete solution to add a Master Page to a site collection which contains: 1.  Master Page Module which contains the Master Page and Page Layout 2.  The Footer Module to add the Footer Web Part 3.  Miscellaneous modules to add images, JQuery, CSS and subsite page 4.  3 features and two feature event receivers: a.  DJGreenCSS, used to add the master page CSS file to Style Sheet Library and an Event Receiver to check it in. b.  DJGreenMaster used to add the Master Page and Page Layout.  In an Event Receiver change the master page to DJGreenMaster , create the footer list and check the files in. c.  DJGreenMasterWebParts add the Footer Web Part to the site collection. I won’t go over the code for this as I will give it to you at the end of this blog post. I have discussed creating a list in code in a previous post.  So what we have is the basis to begin what is germane to this discussion.  I have the first two requirements completed.  I need now to add page web parts and the build the pages in code.  For the page web parts, I will use one downloaded from Codeplex which does not use a SharePoint custom list for simplicity:   Weather Web Part and another downloaded from MSDN which is a SharePoint Custom Calendar Web Part, I had to add some functionality to make the events color coded to exceed the built-in 10 overlays using JQuery!    Here is the solution with the added projects:     Here is a screen shot of the Weather Web Part Deployed:   Here is a screen shot of the Site Calendar with JQuery:     Okay, Now we get to the final item:  To create Publishing pages.   We need to add a feature receiver to the DJGreenMaster project I will name it DJSitePages and also add a Event Receiver:       We will build the page at the site collection level and all of the code necessary will be contained in the event receiver.   Added a reference to the Microsoft.SharePoint.Publishing.dll contained in the ISAPI folder of the 14 Hive.   First we will add some static methods from which we will call  in our Event Receiver:   1: private static void checkOut(string pagename, PublishingPage p) 2: { 3: if (p.Name.Equals(pagename, StringComparison.InvariantCultureIgnoreCase)) 4: { 5: 6: if (p.ListItem.File.CheckOutType == SPFile.SPCheckOutType.None) 7: { 8: p.CheckOut(); 9: } 10:   11: if (p.ListItem.File.CheckOutType == SPFile.SPCheckOutType.Online) 12: { 13: p.CheckIn("initial"); 14: p.CheckOut(); 15: } 16: } 17: } 18: private static void checkin(PublishingPage p,PublishingWeb pw) 19: { 20: SPFile publishFile = p.ListItem.File; 21:   22: if (publishFile.CheckOutType != SPFile.SPCheckOutType.None) 23: { 24:   25: publishFile.CheckIn( 26:   27: "CheckedIn"); 28:   29: publishFile.Publish( 30:   31: "published"); 32: } 33: // In case of content approval, approve the file need to add 34: //pulishing site 35: if (pw.PagesList.EnableModeration) 36: { 37: publishFile.Approve("Initial"); 38: } 39: publishFile.Update(); 40: }   In a Publishing Site, CheckIn and CheckOut  are required when dealing with pages in a publishing site.  Okay lets look at the Feature Activated Event Receiver: 1: public override void FeatureActivated(SPFeatureReceiverProperties properties) 2: { 3:   4:   5:   6: object oParent = properties.Feature.Parent; 7:   8:   9:   10: if (properties.Feature.Parent is SPWeb) 11: { 12:   13: currentWeb = (SPWeb)oParent; 14:   15: currentSite = currentWeb.Site; 16:   17: } 18:   19: else 20: { 21:   22: currentSite = (SPSite)oParent; 23:   24: currentWeb = currentSite.RootWeb; 25:   26: } 27: 28:   29: //create the publishing pages 30: CreatePublishingPage(currentWeb, "Home.aspx", "ThreeColumnLayout.aspx","Home"); 31: //CreatePublishingPage(currentWeb, "Dummy.aspx", "ThreeColumnLayout.aspx","Dummy"); 32: }     Basically we are calling the method Create Publishing Page with parameters:  Current Web, Name of the Page, The Page Layout, Title of the page.  Let’s look at the Create Publishing Page method:   1:   2: private void CreatePublishingPage(SPWeb site, string pageName, string pageLayoutName, string title) 3: { 4: PublishingSite pubSiteCollection = new PublishingSite(site.Site); 5: PublishingWeb pubSite = null; 6: if (pubSiteCollection != null) 7: { 8: // Assign an object to the pubSite variable 9: if (PublishingWeb.IsPublishingWeb(site)) 10: { 11: pubSite = PublishingWeb.GetPublishingWeb(site); 12: } 13: } 14: // Search for the page layout for creating the new page 15: PageLayout currentPageLayout = FindPageLayout(pubSiteCollection, pageLayoutName); 16: // Check or the Page Layout could be found in the collection 17: // if not (== null, return because the page has to be based on 18: // an excisting Page Layout 19: if (currentPageLayout == null) 20: { 21: return; 22: } 23:   24: 25: PublishingPageCollection pages = pubSite.GetPublishingPages(); 26: foreach (PublishingPage p in pages) 27: { 28: //The page allready exists 29: if ((p.Name == pageName)) return; 30:   31: } 32: 33:   34:   35: PublishingPage newPage = pages.Add(pageName, currentPageLayout); 36: newPage.Description = pageName.Replace(".aspx", ""); 37: // Here you can set some properties like: 38: newPage.IncludeInCurrentNavigation = true; 39: newPage.IncludeInGlobalNavigation = true; 40: newPage.Title = title; 41: 42: 43:   44:   45: 46:   47: //build the page 48:   49: 50: switch (pageName) 51: { 52: case "Homer.aspx": 53: checkOut("Courier.aspx", newPage); 54: BuildHomePage(site, newPage); 55: break; 56:   57:   58: default: 59: break; 60: } 61: // newPage.Update(); 62: //Now we can checkin the newly created page to the “pages” library 63: checkin(newPage, pubSite); 64: 65: 66: }     The narrative in what is going on here is: 1.  We need to find out if we are dealing with a Publishing Web.  2.  Get the Page Layout 3.  Create the Page in the pages list. 4.  Based on the page name we build that page.  (Here is where we can add all the methods to build multiple pages.) In the switch we call Build Home Page where all the work is done to add the web parts.  Prior to adding the web parts we need to add references to the two web part projects in the solution. using WeatherWebPart.WeatherWebPart; using CSSharePointCustomCalendar.CustomCalendarWebPart;   We can then reference them in the Build Home Page method.   Let’s look at Build Home Page: 1:   2: private static void BuildHomePage(SPWeb web, PublishingPage pubPage) 3: { 4: // build the pages 5: // Get the web part manager for each page and do the same code as below (copy and paste, change to the web parts for the page) 6: // Part Description 7: SPLimitedWebPartManager mgr = web.GetLimitedWebPartManager(web.Url + "/Pages/Home.aspx", System.Web.UI.WebControls.WebParts.PersonalizationScope.Shared); 8: WeatherWebPart.WeatherWebPart.WeatherWebPart wwp = new WeatherWebPart.WeatherWebPart.WeatherWebPart() { ChromeType = PartChromeType.None, Title = "Todays Weather", AreaCode = "2504627" }; 9: //Dictionary<string, string> wwpDic= new Dictionary<string, string>(); 10: //wwpDic.Add("AreaCode", "2504627"); 11: //setWebPartProperties(wwp, "WeatherWebPart", wwpDic); 12:   13: // Add the web part to a pagelayout Web Part Zone 14: mgr.AddWebPart(wwp, "g_685594D193AA4BBFABEF2FB0C8A6C1DD", 1); 15:   16: CSSharePointCustomCalendar.CustomCalendarWebPart.CustomCalendarWebPart cwp = new CustomCalendarWebPart() { ChromeType = PartChromeType.None, Title = "Corporate Calendar", listName="CorporateCalendar" }; 17:   18: mgr.AddWebPart(cwp, "g_20CBAA1DF45949CDA5D351350462E4C6", 1); 19:   20:   21: pubPage.Update(); 22:   23: } Here is what we are doing: 1.  We got  a reference to the SharePoint Limited Web Part Manager and linked/referenced Home.aspx  2.  Instantiated the a new Weather Web Part and used the Manager to add it to the page in a web part zone identified by ID,  thus the need for a Page Layout where the developer knows the ID’s. 3.  Instantiated the Calendar Web Part and used the Manager to add it to the page. 4. We the called the Publishing Page update method. 5.  Lastly, the Create Publishing Page method checks in the page just created.   Here is a screen shot of the page right after a deploy!       Okay!  I know we could make a home page look much better!  However, I built this whole Integrated solution in less than a day with the caveat that the Green Master was already built!  So what am I saying?  Build you web parts, master pages, etc.  At the very end of the engagement build the pages.  The client will be very happy!  Here is the code for this solution Code

    Read the article

  • Gnome-Network-Manager Config File Migration

    - by Jorge
    I think I have an issue with gnome-network-manager, I used to have a lot of connections configured, Wireless, Wired and VPN. After upgrading to 12.04 (from 11.10) I lost every configuration. I realized that the configs that used to be saved in $HOME/.gconf/system/networking/connections now are being saved in /etc/NetworkManager/system-connections/. I don't know how to migrate my settings to the new config file format Can anybody help me? jorge@thinky:~$ sudo lshw -C network *-network description: Ethernet interface product: 82566MM Gigabit Network Connection vendor: Intel Corporation physical id: 19 bus info: pci@0000:00:19.0 logical name: eth0 version: 03 serial: 00:1f:e2:14:5a:9b capacity: 1Gbit/s width: 32 bits clock: 33MHz capabilities: pm msi bus_master cap_list ethernet physical tp 10bt 10bt-fd 100bt 100bt-fd 1000bt-fd autonegotiation configuration: autonegotiation=on broadcast=yes driver=e1000e driverversion=1.5.1-k firmware=0.3-0 latency=0 link=no multicast=yes port=twisted pair resources: irq:46 memory:fe000000-fe01ffff memory:fe025000-fe025fff ioport:1840(size=32) *-network description: Wireless interface product: PRO/Wireless 4965 AG or AGN [Kedron] Network Connection vendor: Intel Corporation physical id: 0 bus info: pci@0000:03:00.0 logical name: wlan0 version: 61 serial: 00:21:5c:32:c2:e5 width: 64 bits clock: 33MHz capabilities: pm msi pciexpress bus_master cap_list ethernet physical wireless configuration: broadcast=yes driver=iwl4965 driverversion=3.2.0-23-generic-pae firmware=228.61.2.24 ip=192.168.2.103 latency=0 link=yes multicast=yes wireless=IEEE 802.11abgn resources: irq:47 memory:df3fe000-df3fffff jorge@thinky:~$ lsb_release -a No LSB modules are available. Distributor ID: Ubuntu Description: Ubuntu 12.04 LTS Release: 12.04 Codename: precise jorge@thinky:~$ uname -a Linux thinky 3.2.0-23-generic-pae #36-Ubuntu SMP Tue Apr 10 22:19:09 UTC 2012 i686 i686 i386 GNU/Linux jorge@thinky:~$ dpkg -l | grep -i firm ii linux-firmware 1.79 Firmware for Linux kernel drivers

    Read the article

  • I cannot solve the "Install these packages without verification" problem

    - by Yonatan Orlev
    I Googled and Googled and I just cannot find a solution to this problem: sudo apt-get install <whatever> Gives me: WARNING: The following packages cannot be authenticated! and Install these packages without verification [y/N]? I cannot find a decent solution. The closest I got was to run: sudo apt-get install debian-keyring debian-archive-keyring But then, even thought, and against my good judgment I agreed to install the package without confirmation, I get: (I replaced http with XXXX because of forum limitations). Install these packages without verification [y/N]? y Err XXXX://il.archive.ubuntu.com gutsy/universe debian-archive-keyring 2007.02.19-0.1 404 Not Found Err XXXX://il.archive.ubuntu.com gutsy/universe debian-keyring 2005.05.28 404 Not Found Failed to fetch XXXX://il.archive.ubuntu.com/ubuntu/pool/universe/d/debian-archive-keyring/debian-archive-keyring_2007.02.19-0.1_all.deb 404 Not Found Failed to fetch XXXX://il.archive.ubuntu.com/ubuntu/pool/universe/d/debian-keyring/debian-keyring_2005.05.28_all.deb 404 Not Found E: Unable to fetch some archives, maybe run apt-get update or try with --fix-missing? Trying to run apt-get update also does not help: I get tons of "404 Not Found" errors. Can someone please direct me to a good solution to this problem? I cannot understand why this issue is not better documented. There must be a simple solution which allows me to update my list of sources or whatever.

    Read the article

  • Nvidia API mismatch

    - by Oli
    I had planned a day of relaxing with Portal 2 but on starting Steam (for the first time in a couple of weeks) I was greeted with the following message in the terminal: Error: API mismatch: the NVIDIA kernel module has version 270.41.19, but this NVIDIA driver component has version 270.41.06. Please make sure that the kernel module and all NVIDIA driver components have the same version. I'll confess I don't really know what it's talking about when it says driver. The verion of nvidia-current is 270.41.19. I thought that was the driver and module, all in one. I use the X-SWAT PPA and I have noted that the nvidia-settings package has boosted to 275.09.07. As this is just a settings application, I don't think this mismatch has anything to do with this. It's also not the same version as the problem being described. I'd rather not purge back to the standard Nvidia driver as it's less than stable on my GTX580. I would accept an answer that takes the manual setup and makes it recompile when the kernel recompiles (ie, some DKMS wizardry) but it has to work. I don't want to drop back to text-mode every time I restart after a kernel upgrade. Edit: Minecraft works without a single complaint about driver versions. Penumbra dies with roughly the same error when entering a game.

    Read the article

  • Security Alert for CVE-2010-0886 and CVE-2010-0887 Released

    - by eric.maurice
    Hi, this is Eric Maurice again! Oracle just released a Security Alert to announce the availability of fixes for two vulnerabilities (CVE-2010-0886 and CVE-2010-0887) affecting Oracle Java SE and Oracle Java For Business. Both vulnerabilities only affect Java when running in a 32-bit web browser. These vulnerabilities are not present in Java running on servers or standalone Java desktop applications and do not impact any Oracle server based software. The first vulnerability (CVE-2010-0886) affects the Java Deployment Toolkit (version 6 update 10 through 19) on Windows only. The second vulnerability (CVE-2010-0887) affects the Java Plug-in (version 6 update 18 and 19) on Windows, Solaris and Linux. Both vulnerabilities may allow an attacker to run commands on the user's system with the privileges of the user, whose system may have become compromised by visiting a malicious web site. Oracle rated the severity of both vulnerabilities with a CVSS Base Score of 10.0 because many Windows users grant themselves administrative privileges. However, on other platforms, or for Windows users with limited privileges, the CVSS Base Score is only 7.5, because a successful exploitation of these vulnerabilities cannot result in a full compromise of the affected system. Users can quickly determine if they are running vulnerable versions of Java by pointing their browser to http://www.java.com/en/download/help/testvm.xml. Java SE users can visit http://www.java.com and download the most recent release of Java SE to address these vulnerabilities. Because of the criticality of these vulnerabilities, and the publicity they received as a result of their disclosure before the availability of a fix, Oracle recommends that all customers and Java users update their Java installation to the most recent version (6 update 20). For More Information: The advisory for the Security Alert for CVE-2010-0886 and CVE-2010-0887 is located at http://www.oracle.com/technology/deploy/security/alerts/alert-cve-2010-0886.html

    Read the article

  • Floodfill algorithm for GO

    - by user1048606
    The floodfill algorithm is used in the bucket tool in MS paint and photoshop, but it can also be used for GO and minesweeper. http://en.wikipedia.org/wiki/Flood_fill In go you can capture groups of stones, this website portrays it with two stones. http://www.connectedglobe.com/mindy/cap6.html This is my floodfill method in Java, it is not capturing a group of stones and I have no idea why because to me it makes sense. public void floodfill(int turn, int col, int row){ for(int a = col; a<19; a++){ for(int b = row; b<19; b++){ if(turn == black){ if(stones[col][row] == white){ stones[col][row] = 0; floodfill(black, col-1, row); floodfill(black, col+1, row); floodfill(black, col, row-1); floodfill(black, col, row+1); } } } } } It searches up, down, left, right for all the stones on the board. If the stones are white it captures them by making them 0, which represents empty.

    Read the article

  • The NEW MySQL for Developers Course

    - by Antoinette O'Sullivan
    Just Released - The new MySQL for Developers training course.  This 5 day course covers everything a developer needs to know when planning, designing and implementing applications using MySQL, with realistic examples using languages such as Java and PHP. This course gives an in-depth coverage of statements that access and modify data, and shows the student how to design and create other MySQL objects such as triggers, views, and stored procedures. You can take this course: From your desk as a live virtual offering. There are over 800 events on the schedule so you should find one in a timezone near you. The virtual events are also delivered in many languages including English, German, Korean, Latin American Spanish, ... In a classroom. Here is a sample of events on the schedule:  Location  Date  Delivery Language  Prague, Czech Republic 8 October 2012 Czech  Warsaw, Poland 5 November 2012 Polish  Wien, Austria  12 November 2012 German  London, England 15 October 2012 English  Bern, Switzerland  11 April 2013 German  Zurich, Switzerland 14 November 2012 German  Milan, Italy 19 November 2012  Italian  Rome, Italy  15 October 2012  Italian  Gummersbach, Germany  11 February 2013 German  Hamburg, Germany  12 November 2012  German Munich, Germany  10 June 2013  German  Lisbon, Portugal 26 November 2012 European Portuguese  Porto, Portugal 18 February 2013 European Portuguese  Nairobi, Kenya  19 November 2012  English  Madrid, Spain  10 December 2012  Spanish Petaling Jaya, Malaysia  15 October 2012  English  Bangkok, Thailand  29 October 2012  English For further information on the Authentic MySQL Curriculum, to register for an event or express interest in an additional event, go to http://oracle.com/education/mysql.

    Read the article

  • Internet Timeouts with TP-Link TL-WN821N v2 wireless usb stick

    - by user1622959
    A short time after accessing the internet, the browser/download times out. Before the timeout, the internet works OK briefly; afterwards, the wireless is still connected with a strong signal, but every internet access results in a timeout. When I leave the PC for a while, the internet is back just to timeout again as soon as I start using it. The same happens when I reconnect to the router. Also, when I surf the internet, it takes a couple of minutes until the timeout, but when I download something, it times out in a matter of seconds. The wireless adapter works just fine in Windows and internet via ethernet cable works just fine in Ubuntu. Does anyone have the same problem or knows a solution. I use Ubuntu 12.10 x64. The problem occurs since I installed ubuntu (which was a few days ago). Here some stuff that might be usefull: serus@serus-Ubuntu-PC:~$ lsusb Bus 002 Device 002: ID 0cf3:1002 Atheros Communications, Inc. TP-Link TL-WN821N v2 802.11n [Atheros AR9170] serus@serus-Ubuntu-PC:~$ lsmod Module Size Used by carl9170 82083 0 serus@serus-Ubuntu-PC:~$ modinfo carl9170 filename: /lib/modules/3.5.0-21- generic/kernel/drivers/net/wireless/ath/carl9170/carl9170.ko alias: arusb_lnx alias: ar9170usb firmware: carl9170-1.fw description: Atheros AR9170 802.11n USB wireless serus@serus-Ubuntu-PC:~$ iwconfig wlan0 IEEE 802.11bgn ESSID:"virginmedia0137463" Mode:Managed Frequency:2.462 GHz Access Point: A0:21:B7:F8:29:B6 Bit Rate=240 Mb/s Tx-Power=20 dBm Retry long limit:7 RTS thr:off Fragment thr:off Power Management:off Link Quality=66/70 Signal level=-44 dBm Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0 Tx excessive retries:1399 Invalid misc:18 Missed beacon:0 serus@serus-Ubuntu-PC:~$ sudo lshw -C network *-network description: Wireless interface physical id: 1 bus info: usb@2:2 logical name: wlan0 serial: 00:27:19:bb:00:19 capabilities: ethernet physical wireless configuration: broadcast=yes driver=carl9170 driverversion=3.5.0-21-generic firmware=1.9.4 ip=192.168.0.6 link=yes multicast=yes wireless=IEEE 802.11bgn

    Read the article

  • Mouse Speed in GLUT and OpenGL?

    - by CroCo
    I would like to simulate a point that moves in 2D. The input should be the speed of the mouse, so the new position will be computed as following new_position = old_position + delta_time*mouse_velocity As far as I know in GLUT there is no function to acquire the current speed of the mouse between each frame. What I've done so far to compute the delta_time as following void Display() { glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); glColor3f(1.0f, 0.0f, 0.0f); static int delta_t, current_t, previous_t; current_t = glutGet(GLUT_ELAPSED_TIME); delta_t = current_t - previous_t; std::cout << delta_t << std::endl; previous_t = current_t; glutSwapBuffers(); } Where should I start from here? (Note: I have to get the speed of the mouse because I'm modeling a system) Edit: Based on the above code, delta_time fluctuates so much 34 19 2 20 1 20 0 16 1 1 10 21 0 13 1 19 34 0 13 0 6 1 14 Why does this happen?

    Read the article

  • Find possible variations of one item out of multiple baskets.

    - by tugberk
    I have three baskets of balls and each of them has 10 balls which have the following numbers: Basket 1: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 Basket 2: 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 Basket 3: 21, 22, 23, 24, 25, 26, 27, 28, 29, 30 What would be the possible variations If I were to pick one ball from each basket? I guess this is called as Probability in Mathematics but not sure. How would you write this code in C# (or any other programming language) to get the correct results? Edit: Based on @Kilian Foth's comment, here is the solution in C#: class Program { static void Main(string[] args) { IEnumerable<string> basket1 = new List<string> { "1", "2", "3", "4", "5", "6", "7", "8", "9", "10" }; IEnumerable<string> basket2 = new List<string> { "11", "12", "13", "14", "15", "16", "17", "18", "19", "20" }; IEnumerable<string> basket3 = new List<string> { "21", "22", "23", "24", "25", "26", "27", "28", "29", "30" }; foreach (var item1 in basket1) foreach (var item2 in basket2) foreach (var item3 in basket3) { Console.WriteLine("{0}, {1}, {2}", item1, item2, item3); } Console.ReadLine(); } }

    Read the article

  • 2012 EC Election Results

    - by heathervc
    The 2012 Fall Executive Committee Election process is now complete. The ballot closed at midnight pacific time on Monday, 29 October.  Congratulations to Cinterion Wireless Modules GmbH, Credit Suisse, Fujitsu Limited, Hewlett-Packard (all four candidates were ratified),  and CloudBees and London Java Community (two elected candidates) as the new and re-elected merged EC Members. For more information regarding the merged EC, please refer to JSR 355 and the JCP 2.9 Process Document. Ratified Seats: Cinterion Wireless Modules GmbH, Credit Suisse, Fujitsu Limited and Hewlett-Packard Open Election Seats: CloudBees and London Java Community Newly elected EC Members take their seats on Tuesday, 13 November 2012. Detailed Election Results:Number of Eligible Voters: 1131 Percent of Eligible Members Casting Votes: 23.70% Ratified Seats: Candidate Yes Votes (%) No Votes (%) Abstentions Cinterion Wireless Modules GmbH 156 (76) 48 (24) 64 Credit Suisse 205 (85) 35 (15) 28 Fujitsu Limited 195 (85) 35 (15) 38 Hewlett-Packard 182 (81) 44 (19) 42 Open Election Seats: The top two candidates have been elected. Candidate Votes (%) Cisco Systems 37 (7) CloudBees 101 (20) Giuseppe Dell'Abate 6 (1) Liferay, Inc. 35 (7) London Java Community 164 (33) MoroccoJUG 46 (9) North Sixty-One Ltd 26 (5) Software AG 19 (4) ZeroTurnaround 64 (13) None of the above 5 (1) For more information about the candidates who ran for the 2012 Executive Committee Election, please visit the 2012 Executive Committee Elections Nominees page.

    Read the article

  • 7??OTN?????????????&????

    - by OTN-J Master
    7??OTN?????????????&?????????????9?22?~26???????????????????Oracle OpenWorld???JavaOne?????????(????)????7?19????????????????????????????????????????????? 7??????&?????? ?????? ?6/27?????2? iOS??????? Biz????in ?? 7?5?(?)13:30 ~ 17:30 ?????? ??????(??)??????????????iPhone, iPad????????????????????????????????????iOS???????????????????????iOS????(iPhone, iPad??)????????????????????????????????????????????????????????????????? ??????????????2013 Okinawa 7?6?(?)10:00~17:00 ??????????????????????????????????????????Java?? (14?00?~)6 ???????????????????? Java ??????????? Java EE 7 ???????Java?????????????????????????????????????? Java ?????????Tomcat ?????????????????????? Java EE ????????GlassFish Server Open Source Edition????????????????? ?????!??????????????????????? 7?9?(?)13:00 ~ 17:00 ?????? ??????(??)??????????????????????????????????????????????????????????????????????????????(??)??????????????????Oracle GoldenGate????????????????????????????????????????????????????????????????????? ????! ???????? ?106?-???????????????Export/Import 7?10?(?)18:30 ~20:00 ?????? ????????????(??)18?????????????????????! ???????????106????Export/Import ??????????SQL*Loader??????????????????????????? ??????Oracle Database Appliance??? 7?16?(?)15:30 ~ 17:15 ?????? ??????(??)??????????????????????????????????·?????Oracle Database Appliance???????????????????????????????????????????????? ????~!!??????? ?7? ?Oracle Master Bronze Oracle Database 11g ????????? 7?17?(?)18:30~20:00  ???????? ???? ??????? (??)???23???????????????????????????????? ?????????????????ORACLE MASTER Bronze Oracle Database 11g????????????????????????????????????????????????????ORACLE MASTER Bronze???????? ??????????????????? ?????! ?????????/???????????? 7?19?(?)10:00 ~ 17:30 ?????? ??????(??)?Oracle Application Testing Suite??Web?????????????????????????????????????????????????????????????????????????????????????????????????????????????????Oracle Application Testing Suite????????????????????????????????????????????????????? Oracle Optimized Data Center Summit7?25?(?)13:00 ~ 17:30 ?????????7?26?(?)12:30 ~ 16:30 ??????????IT???????????????????????????????????????????????????????????????????????????????????IT????????????????????????????????·???????????????????????????????????????????????????????????????

    Read the article

  • C#/.NET Little Wonders: The Timeout static class

    - by James Michael Hare
    Once again, in this series of posts I look at the parts of the .NET Framework that may seem trivial, but can help improve your code by making it easier to write and maintain. The index of all my past little wonders posts can be found here. When I started the “Little Wonders” series, I really wanted to pay homage to parts of the .NET Framework that are often small but can help in big ways.  The item I have to discuss today really is a very small item in the .NET BCL, but once again I feel it can help make the intention of code much clearer and thus is worthy of note. The Problem - Magic numbers aren’t very readable or maintainable In my first Little Wonders Post (Five Little Wonders That Make Code Better) I mention the TimeSpan factory methods which, I feel, really help the readability of constructed TimeSpan instances. Just to quickly recap that discussion, ask yourself what the TimeSpan specified in each case below is 1: // Five minutes? Five Seconds? 2: var fiveWhat1 = new TimeSpan(0, 0, 5); 3: var fiveWhat2 = new TimeSpan(0, 0, 5, 0); 4: var fiveWhat3 = new TimeSpan(0, 0, 5, 0, 0); You’d think they’d all be the same unit of time, right?  After all, most overloads tend to tack additional arguments on the end.  But this is not the case with TimeSpan, where the constructor forms are:     TimeSpan(int hours, int minutes, int seconds);     TimeSpan(int days, int hours, int minutes, int seconds);     TimeSpan(int days, int hours, int minutes, int seconds, int milliseconds); Notice how in the 4 and 5 parameter version we suddenly have the parameter days slipping in front of hours?  This can make reading constructors like those above much harder.  Fortunately, there are TimeSpan factory methods to help make your intention crystal clear: 1: // Ah! Much clearer! 2: var fiveSeconds = TimeSpan.FromSeconds(5); These are great because they remove all ambiguity from the reader!  So in short, magic numbers in constructors and methods can be ambiguous, and anything we can do to clean up the intention of the developer will make the code much easier to read and maintain. Timeout – Readable identifiers for infinite timeout values In a similar way to TimeSpan, let’s consider specifying timeouts for some of .NET’s (or our own) many methods that allow you to specify timeout periods. For example, in the TPL Task class, there is a family of Wait() methods that can take TimeSpan or int for timeouts.  Typically, if you want to specify an infinite timeout, you’d just call the version that doesn’t take a timeout parameter at all: 1: myTask.Wait(); // infinite wait But there are versions that take the int or TimeSpan for timeout as well: 1: // Wait for 100 ms 2: myTask.Wait(100); 3:  4: // Wait for 5 seconds 5: myTask.Wait(TimeSpan.FromSeconds(5); Now, if we want to specify an infinite timeout to wait on the Task, we could pass –1 (or a TimeSpan set to –1 ms), which what the .NET BCL methods with timeouts use to represent an infinite timeout: 1: // Also infinite timeouts, but harder to read/maintain 2: myTask.Wait(-1); 3: myTask.Wait(TimeSpan.FromMilliseconds(-1)); However, these are not as readable or maintainable.  If you were writing this code, you might make the mistake of thinking 0 or int.MaxValue was an infinite timeout, and you’d be incorrect.  Also, reading the code above it isn’t as clear that –1 is infinite unless you happen to know that is the specified behavior. To make the code like this easier to read and maintain, there is a static class called Timeout in the System.Threading namespace which contains definition for infinite timeouts specified as both int and TimeSpan forms: Timeout.Infinite An integer constant with a value of –1 Timeout.InfiniteTimeSpan A static readonly TimeSpan which represents –1 ms (only available in .NET 4.5+) This makes our calls to Task.Wait() (or any other calls with timeouts) much more clear: 1: // intention to wait indefinitely is quite clear now 2: myTask.Wait(Timeout.Infinite); 3: myTask.Wait(Timeout.InfiniteTimeSpan); But wait, you may say, why would we care at all?  Why not use the version of Wait() that takes no arguments?  Good question!  When you’re directly calling the method with an infinite timeout that’s what you’d most likely do, but what if you are just passing along a timeout specified by a caller from higher up?  Or perhaps storing a timeout value from a configuration file, and want to default it to infinite? For example, perhaps you are designing a communications module and want to be able to shutdown gracefully, but if you can’t gracefully finish in a specified amount of time you want to force the connection closed.  You could create a Shutdown() method in your class, and take a TimeSpan or an int for the amount of time to wait for a clean shutdown – perhaps waiting for client to acknowledge – before terminating the connection.  So, assume we had a pub/sub system with a class to broadcast messages: 1: // Some class to broadcast messages to connected clients 2: public class Broadcaster 3: { 4: // ... 5:  6: // Shutdown connection to clients, wait for ack back from clients 7: // until all acks received or timeout, whichever happens first 8: public void Shutdown(int timeout) 9: { 10: // Kick off a task here to send shutdown request to clients and wait 11: // for the task to finish below for the specified time... 12:  13: if (!shutdownTask.Wait(timeout)) 14: { 15: // If Wait() returns false, we timed out and task 16: // did not join in time. 17: } 18: } 19: } We could even add an overload to allow us to use TimeSpan instead of int, to give our callers the flexibility to specify timeouts either way: 1: // overload to allow them to specify Timeout in TimeSpan, would 2: // just call the int version passing in the TotalMilliseconds... 3: public void Shutdown(TimeSpan timeout) 4: { 5: Shutdown(timeout.TotalMilliseconds); 6: } Notice in case of this class, we don’t assume the caller wants infinite timeouts, we choose to rely on them to tell us how long to wait.  So now, if they choose an infinite timeout, they could use the –1, which is more cryptic, or use Timeout class to make the intention clear: 1: // shutdown the broadcaster, waiting until all clients ack back 2: // without timing out. 3: myBroadcaster.Shutdown(Timeout.Infinite); We could even add a default argument using the int parameter version so that specifying no arguments to Shutdown() assumes an infinite timeout: 1: // Modified original Shutdown() method to add a default of 2: // Timeout.Infinite, works because Timeout.Infinite is a compile 3: // time constant. 4: public void Shutdown(int timeout = Timeout.Infinite) 5: { 6: // same code as before 7: } Note that you can’t default the ShutDown(TimeSpan) overload with Timeout.InfiniteTimeSpan since it is not a compile-time constant.  The only acceptable default for a TimeSpan parameter would be default(TimeSpan) which is zero milliseconds, which specified no wait, not infinite wait. Summary While Timeout.Infinite and Timeout.InfiniteTimeSpan are not earth-shattering classes in terms of functionality, they do give you very handy and readable constant values that you can use in your programs to help increase readability and maintainability when specifying infinite timeouts for various timeouts in the BCL and your own applications. Technorati Tags: C#,CSharp,.NET,Little Wonders,Timeout,Task

    Read the article

  • C#/.NET Little Wonders: Interlocked Read() and Exchange()

    - by James Michael Hare
    Once again, in this series of posts I look at the parts of the .NET Framework that may seem trivial, but can help improve your code by making it easier to write and maintain. The index of all my past little wonders posts can be found here. Last time we discussed the Interlocked class and its Add(), Increment(), and Decrement() methods which are all useful for updating a value atomically by adding (or subtracting).  However, this begs the question of how do we set and read those values atomically as well? Read() – Read a value atomically Let’s begin by examining the following code: 1: public class Incrementor 2: { 3: private long _value = 0; 4:  5: public long Value { get { return _value; } } 6:  7: public void Increment() 8: { 9: Interlocked.Increment(ref _value); 10: } 11: } 12:  It uses an interlocked increment, as we discuss in my previous post (here), so we know that the increment will be thread-safe.  But, to realize what’s potentially wrong we have to know a bit about how atomic reads are in 32 bit and 64 bit .NET environments. When you are dealing with an item smaller or equal to the system word size (such as an int on a 32 bit system or a long on a 64 bit system) then the read is generally atomic, because it can grab all of the bits needed at once.  However, when dealing with something larger than the system word size (reading a long on a 32 bit system for example), it cannot grab the whole value at once, which can lead to some problems since this read isn’t atomic. For example, this means that on a 32 bit system we may read one half of the long before another thread increments the value, and the other half of it after the increment.  To protect us from reading an invalid value in this manner, we can do an Interlocked.Read() to force the read to be atomic (of course, you’d want to make sure any writes or increments are atomic also): 1: public class Incrementor 2: { 3: private long _value = 0; 4:  5: public long Value 6: { 7: get { return Interlocked.Read(ref _value); } 8: } 9:  10: public void Increment() 11: { 12: Interlocked.Increment(ref _value); 13: } 14: } Now we are guaranteed that we will read the 64 bit value atomically on a 32 bit system, thus ensuring our thread safety (assuming all other reads, writes, increments, etc. are likewise protected).  Note that as stated before, and according to the MSDN (here), it isn’t strictly necessary to use Interlocked.Read() for reading 64 bit values on 64 bit systems, but for those still working in 32 bit environments, it comes in handy when dealing with long atomically. Exchange() – Exchanges two values atomically Exchange() lets us store a new value in the given location (the ref parameter) and return the old value as a result. So just as Read() allows us to read atomically, one use of Exchange() is to write values atomically.  For example, if we wanted to add a Reset() method to our Incrementor, we could do something like this: 1: public void Reset() 2: { 3: _value = 0; 4: } But the assignment wouldn’t be atomic on 32 bit systems, since the word size is 32 bits and the variable is a long (64 bits).  Thus our assignment could have only set half the value when a threaded read or increment happens, which would put us in a bad state. So instead, we could write Reset() like this: 1: public void Reset() 2: { 3: Interlocked.Exchange(ref _value, 0); 4: } And we’d be safe again on a 32 bit system. But this isn’t the only reason Exchange() is valuable.  The key comes in realizing that Exchange() doesn’t just set a new value, it returns the old as well in an atomic step.  Hence the name “exchange”: you are swapping the value to set with the stored value. So why would we want to do this?  Well, anytime you want to set a value and take action based on the previous value.  An example of this might be a scheme where you have several tasks, and during every so often, each of the tasks may nominate themselves to do some administrative chore.  Perhaps you don’t want to make this thread dedicated for whatever reason, but want to be robust enough to let any of the threads that isn’t currently occupied nominate itself for the job.  An easy and lightweight way to do this would be to have a long representing whether someone has acquired the “election” or not.  So a 0 would indicate no one has been elected and 1 would indicate someone has been elected. We could then base our nomination strategy as follows: every so often, a thread will attempt an Interlocked.Exchange() on the long and with a value of 1.  The first thread to do so will set it to a 1 and return back the old value of 0.  We can use this to show that they were the first to nominate and be chosen are thus “in charge”.  Anyone who nominates after that will attempt the same Exchange() but will get back a value of 1, which indicates that someone already had set it to a 1 before them, thus they are not elected. Then, the only other step we need take is to remember to release the election flag once the elected thread accomplishes its task, which we’d do by setting the value back to 0.  In this way, the next thread to nominate with Exchange() will get back the 0 letting them know they are the new elected nominee. Such code might look like this: 1: public class Nominator 2: { 3: private long _nomination = 0; 4: public bool Elect() 5: { 6: return Interlocked.Exchange(ref _nomination, 1) == 0; 7: } 8: public bool Release() 9: { 10: return Interlocked.Exchange(ref _nomination, 0) == 1; 11: } 12: } There’s many ways to do this, of course, but you get the idea.  Running 5 threads doing some “sleep” work might look like this: 1: var nominator = new Nominator(); 2: var random = new Random(); 3: Parallel.For(0, 5, i => 4: { 5:  6: for (int j = 0; j < _iterations; ++j) 7: { 8: if (nominator.Elect()) 9: { 10: // elected 11: Console.WriteLine("Elected nominee " + i); 12: Thread.Sleep(random.Next(100, 5000)); 13: nominator.Release(); 14: } 15: else 16: { 17: // not elected 18: Console.WriteLine("Did not elect nominee " + i); 19: } 20: // sleep before check again 21: Thread.Sleep(1000); 22: } 23: }); And would spit out results like: 1: Elected nominee 0 2: Did not elect nominee 2 3: Did not elect nominee 1 4: Did not elect nominee 4 5: Did not elect nominee 3 6: Did not elect nominee 3 7: Did not elect nominee 1 8: Did not elect nominee 2 9: Did not elect nominee 4 10: Elected nominee 3 11: Did not elect nominee 2 12: Did not elect nominee 1 13: Did not elect nominee 4 14: Elected nominee 0 15: Did not elect nominee 2 16: Did not elect nominee 4 17: ... Another nice thing about the Interlocked.Exchange() is it can be used to thread-safely set pretty much anything 64 bits or less in size including references, pointers (in unsafe mode), floats, doubles, etc.  Summary So, now we’ve seen two more things we can do with Interlocked: reading and exchanging a value atomically.  Read() and Exchange() are especially valuable for reading/writing 64 bit values atomically in a 32 bit system.  Exchange() has value even beyond simply atomic writes by using the Exchange() to your advantage, since it reads and set the value atomically, which allows you to do lightweight nomination systems. There’s still a few more goodies in the Interlocked class which we’ll explore next time! Technorati Tags: C#,CSharp,.NET,Little Wonders,Interlocked

    Read the article

  • yui compressor maven plugin doesnt compress the js files

    - by hanumant
    I am using yui compressor to compress the js files in my web app. I have configured the plugin as indicated on yui maven plugin site yui compressor maven plugin. This is the pom plugin conf <plugin> <groupId>net.sf.alchim</groupId> <artifactId>yuicompressor-maven-plugin</artifactId> <version>0.7.1</version> <executions> <execution> <phase>compile</phase> <goals> <goal>jslint</goal> <goal>compress</goal> </goals> </execution> </executions> <configuration> <failOnWarning>true</failOnWarning> <nosuffix>true</nosuffix> <force>true</force> <aggregations> <aggregation> <!-- remove files after aggregation (default: false) --> <removeIncluded>false</removeIncluded> <!-- insert new line after each concatenation (default: false) --> <insertNewLine>false</insertNewLine> <output>${project.basedir}/${webcontent.dir}/js/compressedAll.js</output> <!-- files to include, path relative to output's directory or absolute path--> <!--inputDir>base directory for non absolute includes, default to parent dir of output</inputDir--> <includes> <include>**/autocomplete.js</include> <include>**/calendar.js</include> <include>**/dialogs.js</include> <include>**/download.js</include> <include>**/folding.js</include> <include>**/jquery-1.4.2.min.js</include> <include>**/jquery.bgiframe.min.js</include> <include>**/jquery.loadmask.js</include> <include>**/jquery.printelement-1.1.js</include> <include>**/jquery.tablesorter.mod.js</include> <include>**/jquery.tablesorter.pager.js</include> <include>**/jquery.dialogs.plugin.js</include> <include>**/jquery.ui.autocomplete.js</include> <include>**/jquery.validate.js</include> <include>**/jquery-ui-1.8.custom.min.js</include> <include>**/languageDropdown.js</include> <include>**/messages.js</include> <include>**/print.js</include> <include>**/tables.js</include> <include>**/tabs.js</include> <include>**/uwTooltip.js</include> </includes> <!-- files to exclude, path relative to output's directory--> </aggregation> </aggregations> </configuration> <dependencies> <dependency> <groupId>rhino</groupId> <artifactId>js</artifactId> <scope>compile</scope> <version>1.6R5</version> </dependency> <dependency> <groupId>org.apache.maven</groupId> <artifactId>maven-plugin-api</artifactId> <version>2.0.7</version> <scope>provided</scope> </dependency> <dependency> <groupId>org.apache.maven</groupId> <artifactId>maven-project</artifactId> <version>2.0.7</version> <scope>provided</scope> </dependency><dependency> <groupId>net.sf.retrotranslator</groupId> <artifactId>retrotranslator-runtime</artifactId> <version>1.2.9</version> <scope>runtime</scope> </dependency> </dependencies> </plugin> And here is the log at compress time These will use the artifact files already in the core ClassRealm instead, to allow them to be included in PluginDescriptor.getArtifacts(). [DEBUG] Configuring mojo 'net.sf.alchim:yuicompressor-maven-plugin:0.7.1:jslint' [DEBUG] (f) failOnWarning = true [DEBUG] (f) jswarn = true [DEBUG] (f) outputDirectory = C:\test\target\classes [DEBUG] (f) project = MavenProject: com.test.test1:test2:19-SNAPSHOT @ C:\test\pom.xml [DEBUG] (f) resources = [Resource {targetPath: null, filtering: false, FileSet {directory: C:\test\src, PatternSet [includes: {}, excludes: {**/*.class, **/*.java, site/*}]}}] [DEBUG] (f) sourceDirectory = C:\test\src\..\js [DEBUG] (f) warSourceDirectory = C:\test\src\main\webapp [DEBUG] (f) webappDirectory = C:\test\target\test2-19-SNAPSHOT [DEBUG] -- end configuration -- [INFO] [yuicompressor:jslint {execution: default}] [INFO] nb warnings: 0, nb errors: 0 [DEBUG] Configuring mojo 'net.sf.alchim:yuicompressor-maven-plugin:0.7.1:compress' -- [DEBUG] (f) removeIncluded = false [DEBUG] (f) insertNewLine = false [DEBUG] (f) output = C:\test\WebContent\js\compressedAll.js [DEBUG] (f) includes = [**/autocomplete.js, **/calendar.js, **/dialogs.js, **/download.js, **/folding.js, **/jquery-1.4.2.min.js, **/jquery.bgifram e.min.js, **/jquery.loadmask.js, **/jquery.printelement-1.1.js, **/jquery.tablesorter.mod.js, **/jquery.tablesorter.pager.js, **/jquery.dialogs.p lugin.js, **/jquery.ui.autocomplete.js, **/jquery.validate.js, **/jquery-ui-1.8.custom.min.js, **/languageDropdown.js, **/messages.js, **/print.js, * */tables.js, **/tabs.js, **/uwTooltip.js] [DEBUG] (f) aggregations = [net.sf.alchim.mojo.yuicompressor.Aggregation@65646564] [DEBUG] (f) disableOptimizations = false [DEBUG] (f) encoding = Cp1252 [DEBUG] (f) failOnWarning = true [DEBUG] (f) force = true [DEBUG] (f) gzip = false [DEBUG] (f) jswarn = true [DEBUG] (f) linebreakpos = 0 [DEBUG] (f) nomunge = false [DEBUG] (f) nosuffix = true [DEBUG] (f) outputDirectory = C:\test\target\classes [DEBUG] (f) preserveAllSemiColons = false [DEBUG] (f) project = MavenProject: com.test.test1:test2:19-SNAPSHOT @ C:\test\pom.xml [DEBUG] (f) resources = [Resource {targetPath: null, filtering: false, FileSet {directory: C:\test\src, PatternSet [includes: {}, excludes: {**/*.class, **/*.java, site/*}]}}] [DEBUG] (f) sourceDirectory = C:\test\src\..\js [DEBUG] (f) statistics = true [DEBUG] (f) suffix = -min [DEBUG] (f) warSourceDirectory = C:\test\src\main\webapp [DEBUG] (f) webappDirectory = C:\test\target\test2-19-SNAPSHOT [DEBUG] -- end configuration -- [INFO] [yuicompressor:compress {execution: default}] [INFO] generate aggregation : C:\test\WebContent\js\compressedAll.js [INFO] compressedAll.js (407505b) [INFO] nb warnings: 0, nb errors: 0 [DEBUG] Configuring mojo 'org.apache.maven.plugins:maven-resources-plugin:2.2:testResources' -- [DEBUG] (f) filters = [] [DEBUG] (f) outputDirectory = C:\test\target\test-classes [DEBUG] (f) project = MavenProject: com.test.test1:test2:19-SNAPSHOT @ C:\test\pom.xml [DEBUG] (f) resources = [Resource {targetPath: null, filtering: false, FileSet {directory: C:\test\test , PatternSet [includes: {}, excludes: {**/*.class, **/*.java}]}}] [DEBUG] -- end configuration -- The problem is the files are getting aggregated into one file but without compressing. The link above uses version 1.1 and the plugin version I am using is 0.7.1. Is this going to make any diff. Can someone tell what is wrong here. PS: I have obfuscated some text in log to follow the compliance in my firm. So you may find it mismatching somewhere.

    Read the article

  • Python - pickling fails for numpy.void objects

    - by I82Much
    >>> idmapfile = open("idmap", mode="w") >>> pickle.dump(idMap, idmapfile) >>> idmapfile.close() >>> idmapfile = open("idmap") >>> unpickled = pickle.load(idmapfile) >>> unpickled == idMap False idMap[1] {1537: (552, 1, 1537, 17.793827056884766, 3), 1540: (4220, 1, 1540, 19.31205940246582, 3), 1544: (592, 1, 1544, 18.129131317138672, 3), 1675: (529, 1, 1675, 18.347782135009766, 3), 1550: (4048, 1, 1550, 19.31205940246582, 3), 1424: (1528, 1, 1424, 19.744396209716797, 3), 1681: (1265, 1, 1681, 19.596025466918945, 3), 1560: (3457, 1, 1560, 20.530569076538086, 3), 1690: (477, 1, 1690, 17.395542144775391, 3), 1691: (554, 1, 1691, 13.446117401123047, 3), 1436: (3010, 1, 1436, 19.596025466918945, 3), 1434: (3183, 1, 1434, 19.744396209716797, 3), 1441: (3570, 1, 1441, 20.589576721191406, 3), 1435: (476, 1, 1435, 19.640911102294922, 3), 1444: (527, 1, 1444, 17.98480224609375, 3), 1478: (1897, 1, 1478, 19.596025466918945, 3), 1575: (614, 1, 1575, 19.371648788452148, 3), 1586: (2189, 1, 1586, 19.31205940246582, 3), 1716: (3470, 1, 1716, 19.158674240112305, 3), 1590: (2278, 1, 1590, 19.596025466918945, 3), 1463: (991, 1, 1463, 19.31205940246582, 3), 1594: (1890, 1, 1594, 19.596025466918945, 3), 1467: (1087, 1, 1467, 19.31205940246582, 3), 1596: (3759, 1, 1596, 19.744396209716797, 3), 1602: (3011, 1, 1602, 20.530569076538086, 3), 1547: (490, 1, 1547, 17.994071960449219, 3), 1605: (658, 1, 1605, 19.31205940246582, 3), 1606: (1794, 1, 1606, 16.964881896972656, 3), 1719: (1826, 1, 1719, 19.596025466918945, 3), 1617: (583, 1, 1617, 11.894925117492676, 3), 1492: (3441, 1, 1492, 20.500667572021484, 3), 1622: (3215, 1, 1622, 19.31205940246582, 3), 1628: (2761, 1, 1628, 19.744396209716797, 3), 1502: (1563, 1, 1502, 19.596025466918945, 3), 1632: (1108, 1, 1632, 15.457141876220703, 3), 1468: (3779, 1, 1468, 19.596025466918945, 3), 1642: (3970, 1, 1642, 19.744396209716797, 3), 1518: (612, 1, 1518, 18.570245742797852, 3), 1647: (854, 1, 1647, 16.964881896972656, 3), 1650: (2099, 1, 1650, 20.439058303833008, 3), 1651: (540, 1, 1651, 18.552841186523438, 3), 1653: (613, 1, 1653, 19.237197875976563, 3), 1532: (537, 1, 1532, 18.885730743408203, 3)} >>> unpickled[1] {1537: (64880, 1638, 56700, -1.0808743559293829e+18, 152), 1540: (64904, 1638, 0, 0.0, 0), 1544: (54472, 1490, 0, 0.0, 0), 1675: (6464, 1509, 0, 0.0, 0), 1550: (43592, 1510, 0, 0.0, 0), 1424: (43616, 1510, 0, 0.0, 0), 1681: (0, 0, 0, 0.0, 0), 1560: (400, 152, 400, 2.1299736657737219e-43, 0), 1690: (408, 152, 408, 2.7201111331839077e+26, 34), 1435: (424, 152, 61512, 1.0122952080313192e-39, 0), 1436: (400, 152, 400, 20.250289916992188, 3), 1434: (424, 152, 62080, 1.0122952080313192e-39, 0), 1441: (400, 152, 400, 12.250144958496094, 3), 1691: (424, 152, 42608, 15.813941955566406, 3), 1444: (400, 152, 400, 19.625289916992187, 3), 1606: (424, 152, 42432, 5.2947192852601414e-22, 41), 1575: (400, 152, 400, 6.2537390010262572e-36, 0), 1586: (424, 152, 42488, 1.0122601755697111e-39, 0), 1716: (400, 152, 400, 6.2537390010262572e-36, 0), 1590: (424, 152, 64144, 1.0126357235581501e-39, 0), 1463: (400, 152, 400, 6.2537390010262572e-36, 0), 1594: (424, 152, 32672, 17.002994537353516, 3), 1467: (400, 152, 400, 19.750289916992187, 3), 1596: (424, 152, 7176, 1.0124003054161436e-39, 0), 1602: (400, 152, 400, 18.500289916992188, 3), 1547: (424, 152, 7000, 1.0124003054161436e-39, 0), 1605: (400, 152, 400, 20.500289916992188, 3), 1478: (424, 152, 42256, -6.0222748507426518e+30, 222), 1719: (400, 152, 400, 6.2537390010262572e-36, 0), 1617: (424, 152, 16472, 1.0124283313854301e-39, 0), 1492: (400, 152, 400, 6.2537390010262572e-36, 0), 1622: (424, 152, 35304, 1.0123190301052127e-39, 0), 1628: (400, 152, 400, 6.2537390010262572e-36, 0), 1502: (424, 152, 63152, 19.627988815307617, 3), 1632: (400, 152, 400, 19.375289916992188, 3), 1468: (424, 152, 38088, 1.0124213248931084e-39, 0), 1642: (400, 152, 400, 6.2537390010262572e-36, 0), 1518: (424, 152, 63896, 1.0127436235399031e-39, 0), 1647: (400, 152, 400, 6.2537390010262572e-36, 0), 1650: (424, 152, 53424, 16.752857208251953, 3), 1651: (400, 152, 400, 19.250289916992188, 3), 1653: (424, 152, 50624, 1.0126497365427934e-39, 0), 1532: (400, 152, 400, 6.2537390010262572e-36, 0)} The keys come out fine, the values are screwed up. I tried same thing loading file in binary mode; didn't fix the problem. Any idea what I'm doing wrong? Edit: Here's the code with binary. Note that the values are different in the unpickled object. >>> idmapfile = open("idmap", mode="wb") >>> pickle.dump(idMap, idmapfile) >>> idmapfile.close() >>> idmapfile = open("idmap", mode="rb") >>> unpickled = pickle.load(idmapfile) >>> unpickled==idMap False >>> unpickled[1] {1537: (12176, 2281, 56700, -1.0808743559293829e+18, 152), 1540: (0, 0, 15934, 2.7457842047810522e+26, 108), 1544: (400, 152, 400, 4.9518498821046956e+27, 53), 1675: (408, 152, 408, 2.7201111331839077e+26, 34), 1550: (456, 152, 456, -1.1349175514578289e+18, 152), 1424: (432, 152, 432, 4.5939047815653343e-40, 11), 1681: (408, 152, 408, 2.1299736657737219e-43, 0), 1560: (376, 152, 376, 2.1299736657737219e-43, 0), 1690: (376, 152, 376, 2.1299736657737219e-43, 0), 1435: (376, 152, 376, 2.1299736657737219e-43, 0), 1436: (376, 152, 376, 2.1299736657737219e-43, 0), 1434: (376, 152, 376, 2.1299736657737219e-43, 0), 1441: (376, 152, 376, 2.1299736657737219e-43, 0), 1691: (376, 152, 376, 2.1299736657737219e-43, 0), 1444: (376, 152, 376, 2.1299736657737219e-43, 0), 1606: (25784, 2281, 376, -3.2883343074537754e+26, 34), 1575: (24240, 2281, 376, 2.1299736657737219e-43, 0), 1586: (24240, 2281, 376, 2.1299736657737219e-43, 0), 1716: (24240, 2281, 376, -3.0093091599657311e-35, 26), 1590: (24240, 2281, 376, 2.1299736657737219e-43, 0), 1463: (24240, 2281, 376, 2.1299736657737219e-43, 0), 1594: (24240, 2281, 376, -4123208450048.0, 196), 1467: (25784, 2281, 376, 2.1299736657737219e-43, 0), 1596: (25784, 2281, 376, 2.1299736657737219e-43, 0), 1602: (25784, 2281, 376, -5.9963281433905448e+26, 76), 1547: (25784, 2281, 376, -218106240.0, 139), 1605: (25784, 2281, 376, -3.7138649803377281e+27, 56), 1478: (376, 152, 376, 2.1299736657737219e-43, 0), 1719: (25784, 2281, 376, 2.1299736657737219e-43, 0), 1617: (25784, 2281, 376, -1.4411779941597184e+17, 237), 1492: (25784, 2281, 376, 2.8596493694487798e-30, 80), 1622: (25784, 2281, 376, 184686084096.0, 93), 1628: (1336, 152, 1336, 3.1691839245470052e+29, 179), 1502: (1272, 152, 1272, -5.2042207205116645e-17, 99), 1632: (1208, 152, 1208, 2.1299736657737219e-43, 0), 1468: (1144, 152, 1144, 2.1299736657737219e-43, 0), 1642: (1080, 152, 1080, 2.1299736657737219e-43, 0), 1518: (1016, 152, 1016, 4.0240902787680023e+35, 145), 1647: (952, 152, 952, -985172619034624.0, 237), 1650: (888, 152, 888, 12094787289088.0, 66), 1651: (824, 152, 824, 2.1299736657737219e-43, 0), 1653: (760, 152, 760, 0.00018310768064111471, 238), 1532: (696, 152, 696, 8.8978061885676389e+26, 125)} OK I've isolated the problem, but don't know why it's so. First, apparently what I'm pickling are not tuples (though they look like it), but instead numpy.void types. Here is a series to illustrate the problem. first = run0.detections[0] >>> first (1, 19, 1578, 82.637763977050781, 1) >>> type(first) <type 'numpy.void'> >>> firstTuple = tuple(first) >>> theFile = open("pickleTest", "w") >>> pickle.dump(first, theFile) >>> theTupleFile = open("pickleTupleTest", "w") >>> pickle.dump(firstTuple, theTupleFile) >>> theFile.close() >>> theTupleFile.close() >>> first (1, 19, 1578, 82.637763977050781, 1) >>> firstTuple (1, 19, 1578, 82.637764, 1) >>> theFile = open("pickleTest", "r") >>> theTupleFile = open("pickleTupleTest", "r") >>> unpickledTuple = pickle.load(theTupleFile) >>> unpickledVoid = pickle.load(theFile) >>> type(unpickledVoid) <type 'numpy.void'> >>> type(unpickledTuple) <type 'tuple'> >>> unpickledTuple (1, 19, 1578, 82.637764, 1) >>> unpickledTuple == firstTuple True >>> unpickledVoid == first False >>> unpickledVoid (7936, 1705, 56700, -1.0808743559293829e+18, 152) >>> first (1, 19, 1578, 82.637763977050781, 1)

    Read the article

  • ssh - "Connection closed by xxx.xxx.xxx.xxx" - using password

    - by Michael B
    I attempted to create an new user account that I wish to use to log in using ssh. I did this (in CentOs): /usr/sbin/adduser -d /home/testaccount -s /bin/bash user passwd testaccount This is the error I receive when trying to log in via ssh: ~/.ssh$ ssh -v [email protected] OpenSSH_5.1p1 Debian-5ubuntu1, OpenSSL 0.9.8g 19 Oct 2007 debug1: Reading configuration data /etc/ssh/ssh_config debug1: Applying options for * debug1: Connecting to xxx.xxx.xxx [xxx.xxx.xxx.xxx] port 22. debug1: Connection established. debug1: identity file /home/user/.ssh/identity type -1 debug1: identity file /home/user/.ssh/id_rsa type 1 debug1: Checking blacklist file /usr/share/ssh/blacklist.RSA-2048 debug1: Checking blacklist file /etc/ssh/blacklist.RSA-2048 debug1: identity file /home/user/.ssh/id_dsa type -1 debug1: Remote protocol version 2.0, remote software version OpenSSH_4.3 debug1: match: OpenSSH_4.3 pat OpenSSH_4* debug1: Enabling compatibility mode for protocol 2.0 debug1: Local version string SSH-2.0-OpenSSH_5.1p1 Debian-5ubuntu1 debug1: SSH2_MSG_KEXINIT sent debug1: SSH2_MSG_KEXINIT received debug1: kex: server->client aes128-cbc hmac-md5 none debug1: kex: client->server aes128-cbc hmac-md5 none debug1: SSH2_MSG_KEX_DH_GEX_REQUEST(1024<1024<8192) sent debug1: expecting SSH2_MSG_KEX_DH_GEX_GROUP debug1: SSH2_MSG_KEX_DH_GEX_INIT sent debug1: expecting SSH2_MSG_KEX_DH_GEX_REPLY debug1: Host 'xxx.xxx.xxx.xxx' is known and matches the RSA host key. debug1: Found key in /home/user/.ssh/known_hosts:8 debug1: ssh_rsa_verify: signature correct debug1: SSH2_MSG_NEWKEYS sent debug1: expecting SSH2_MSG_NEWKEYS debug1: SSH2_MSG_NEWKEYS received debug1: SSH2_MSG_SERVICE_REQUEST sent debug1: SSH2_MSG_SERVICE_ACCEPT received debug1: Authentications that can continue: publickey,gssapi-with-mic,password debug1: Next authentication method: gssapi-with-mic debug1: Unspecified GSS failure. Minor code may provide more information No credentials cache found debug1: Unspecified GSS failure. Minor code may provide more information No credentials cache found debug1: Unspecified GSS failure. Minor code may provide more information debug1: Next authentication method: publickey debug1: Offering public key: /home/user/.ssh/id_rsa debug1: Authentications that can continue: publickey,gssapi-with-mic,password debug1: Trying private key: /home/user/.ssh/identity debug1: Trying private key: /home/user/.ssh/id_dsa debug1: Next authentication method: password testaccount@xxx's password: Connection closed by xxx.xxx.xxx.xxx The "connection closed" message appeared immediately after entering the password (if I enter the wrong password it waits and then prompts for another password) I am able to log in from the same computer using other accounts that had been setup previously. When logged into the remote machine I am able to do 'su testaccount' Thanks for your time.

    Read the article

  • Revisiting ANTS Performance Profiler 7.4

    - by James Michael Hare
    Last year, I did a small review on the ANTS Performance Profiler 6.3, now that it’s a year later and a major version number higher, I thought I’d revisit the review and revise my last post. This post will take the same examples as the original post and update them to show what’s new in version 7.4 of the profiler. Background A performance profiler’s main job is to keep track of how much time is typically spent in each unit of code. This helps when we have a program that is not running at the performance we expect, and we want to know where the program is experiencing issues. There are many profilers out there of varying capabilities. Red Gate’s typically seem to be the very easy to “jump in” and get started with very little training required. So let’s dig into the Performance Profiler. I’ve constructed a very crude program with some obvious inefficiencies. It’s a simple program that generates random order numbers (or really could be any unique identifier), adds it to a list, sorts the list, then finds the max and min number in the list. Ignore the fact it’s very contrived and obviously inefficient, we just want to use it as an example to show off the tool: 1: // our test program 2: public static class Program 3: { 4: // the number of iterations to perform 5: private static int _iterations = 1000000; 6: 7: // The main method that controls it all 8: public static void Main() 9: { 10: var list = new List<string>(); 11: 12: for (int i = 0; i < _iterations; i++) 13: { 14: var x = GetNextId(); 15: 16: AddToList(list, x); 17: 18: var highLow = GetHighLow(list); 19: 20: if ((i % 1000) == 0) 21: { 22: Console.WriteLine("{0} - High: {1}, Low: {2}", i, highLow.Item1, highLow.Item2); 23: Console.Out.Flush(); 24: } 25: } 26: } 27: 28: // gets the next order id to process (random for us) 29: public static string GetNextId() 30: { 31: var random = new Random(); 32: var num = random.Next(1000000, 9999999); 33: return num.ToString(); 34: } 35: 36: // add it to our list - very inefficiently! 37: public static void AddToList(List<string> list, string item) 38: { 39: list.Add(item); 40: list.Sort(); 41: } 42: 43: // get high and low of order id range - very inefficiently! 44: public static Tuple<int,int> GetHighLow(List<string> list) 45: { 46: return Tuple.Create(list.Max(s => Convert.ToInt32(s)), list.Min(s => Convert.ToInt32(s))); 47: } 48: } So let’s run it through the profiler and see what happens! Visual Studio Integration First, let’s look at how the ANTS profilers integrate with Visual Studio’s menu system. Once you install the ANTS profilers, you will get an ANTS menu item with several options: Notice that you can either Profile Performance or Launch ANTS Performance Profiler. These sound similar but achieve two slightly different actions: Profile Performance: this immediately launches the profiler with all defaults selected to profile the active project in Visual Studio. Launch ANTS Performance Profiler: this launches the profiler much the same way as starting it from the Start Menu. The profiler will pre-populate the application and path information, but allow you to change the settings before beginning the profile run. So really, the main difference is that Profile Performance immediately begins profiling with the default selections, where Launch ANTS Performance Profiler allows you to change the defaults and attach to an already-running application. Let’s Fire it Up! So when you fire up ANTS either via Start Menu or Launch ANTS Performance Profiler menu in Visual Studio, you are presented with a very simple dialog to get you started: Notice you can choose from many different options for application type. You can profile executables, services, web applications, or just attach to a running process. In fact, in version 7.4 we see two new options added: ASP.NET Web Application (IIS Express) SharePoint web application (IIS) So this gives us an additional way to profile ASP.NET applications and the ability to profile SharePoint applications as well. You can also choose your level of detail in the Profiling Mode drop down. If you choose Line-Level and method-level timings detail, you will get a lot more detail on the method durations, but this will also slow down profiling somewhat. If you really need the profiler to be as unintrusive as possible, you can change it to Sample method-level timings. This is performing very light profiling, where basically the profiler collects timings of a method by examining the call-stack at given intervals. Which method you choose depends a lot on how much detail you need to find the issue and how sensitive your program issues are to timing. So for our example, let’s just go with the line and method timing detail. So, we check that all the options are correct (if you launch from VS2010, the executable and path are filled in already), and fire it up by clicking the [Start Profiling] button. Profiling the Application Once you start profiling the application, you will see a real-time graph of CPU usage that will indicate how much your application is using the CPU(s) on your system. During this time, you can select segments of the graph and bookmark them, giving them mnemonic names. This can be useful if you want to compare performance in one part of the run to another part of the run. Notice that once you select a block, it will give you the call tree breakdown for that selection only, and the relative performance of those calls. Once you feel you have collected enough information, you can click [Stop Profiling] to stop the application run and information collection and begin a more thorough analysis. Analyzing Method Timings So now that we’ve halted the run, we can look around the GUI and see what we can see. By default, the times are shown in terms of percentage of time of the total run of the application, though you can change it in the View menu item to milliseconds, ticks, or seconds as well. This won’t affect the percentages of methods, it only affects what units the times are shown. Notice also that the major hotspot seems to be in a method without source, ANTS Profiler will filter these out by default, but you can right-click on the line and remove the filter to see more detail. This proves especially handy when a bottleneck is due to a method in the BCL. So now that we’ve removed the filter, we see a bit more detail: In addition, ANTS Performance Profiler gives you the ability to decompile the methods without source so that you can dive even deeper, though typically this isn’t necessary for our purposes. When looking at timings, there are generally two types of timings for each method call: Time: This is the time spent ONLY in this method, not including calls this method makes to other methods. Time With Children: This is the total of time spent in both this method AND including calls this method makes to other methods. In other words, the Time tells you how much work is being done exclusively in this method, and the Time With Children tells you how much work is being done inclusively in this method and everything it calls. You can also choose to display the methods in a tree or in a grid. The tree view is the default and it shows the method calls arranged in terms of the tree representing all method calls and the parent method that called them, etc. This is useful for when you find a hot-spot method, you can see who is calling it to determine if the problem is the method itself, or if it is being called too many times. The grid method represents each method only once with its totals and is useful for quickly seeing what method is the trouble spot. In addition, you can choose to display Methods with source which are generally the methods you wrote (as opposed to native or BCL code), or Any Method which shows not only your methods, but also native calls, JIT overhead, synchronization waits, etc. So these are just two ways of viewing the same data, and you’re free to choose the organization that best suits what information you are after. Analyzing Method Source If we look at the timings above, we see that our AddToList() method (and in particular, it’s call to the List<T>.Sort() method in the BCL) is the hot-spot in this analysis. If ANTS sees a method that is consuming the most time, it will flag it as a hot-spot to help call out potential areas of concern. This doesn’t mean the other statistics aren’t meaningful, but that the hot-spot is most likely going to be your biggest bang-for-the-buck to concentrate on. So let’s select the AddToList() method, and see what it shows in the source window below: Notice the source breakout in the bottom pane when you select a method (from either tree or grid view). This shows you the timings in this method per line of code. This gives you a major indicator of where the trouble-spot in this method is. So in this case, we see that performing a Sort() on the List<T> after every Add() is killing our performance! Of course, this was a very contrived, duh moment, but you’d be surprised how many performance issues become duh moments. Note that this one line is taking up 86% of the execution time of this application! If we eliminate this bottleneck, we should see drastic improvement in the performance. So to fix this, if we still wanted to maintain the List<T> we’d have many options, including: delay Sort() until after all Add() methods, using a SortedSet, SortedList, or SortedDictionary depending on which is most appropriate, or forgoing the sorting all together and using a Dictionary. Rinse, Repeat! So let’s just change all instances of List<string> to SortedSet<string> and run this again through the profiler: Now we see the AddToList() method is no longer our hot-spot, but now the Max() and Min() calls are! This is good because we’ve eliminated one hot-spot and now we can try to correct this one as well. As before, we can then optimize this part of the code (possibly by taking advantage of the fact the list is now sorted and returning the first and last elements). We can then rinse and repeat this process until we have eliminated as many bottlenecks as possible. Calls by Web Request Another feature that was added recently is the ability to view .NET methods grouped by the HTTP requests that caused them to run. This can be helpful in determining which pages, web services, etc. are causing hot spots in your web applications. Summary If you like the other ANTS tools, you’ll like the ANTS Performance Profiler as well. It is extremely easy to use with very little product knowledge required to get up and running. There are profilers built into the higher product lines of Visual Studio, of course, which are also powerful and easy to use. But for quickly jumping in and finding hot spots rapidly, Red Gate’s Performance Profiler 7.4 is an excellent choice. Technorati Tags: Influencers,ANTS,Performance Profiler,Profiler

    Read the article

  • C#/.NET &ndash; Finding an Item&rsquo;s Index in IEnumerable&lt;T&gt;

    - by James Michael Hare
    Sorry for the long blogging hiatus.  First it was, of course, the holidays hustle and bustle, then my brother and his wife gave birth to their son, so I’ve been away from my blogging for two weeks. Background: Finding an item’s index in List<T> is easy… Many times in our day to day programming activities, we want to find the index of an item in a collection.  Now, if we have a List<T> and we’re looking for the item itself this is trivial: 1: // assume have a list of ints: 2: var list = new List<int> { 1, 13, 42, 64, 121, 77, 5, 99, 132 }; 3:  4: // can find the exact item using IndexOf() 5: var pos = list.IndexOf(64); This will return the position of the item if it’s found, or –1 if not.  It’s easy to see how this works for primitive types where equality is well defined.  For complex types, however, it will attempt to compare them using EqualityComparer<T>.Default which, in a nutshell, relies on the object’s Equals() method. So what if we want to search for a condition instead of equality?  That’s also easy in a List<T> with the FindIndex() method: 1: // assume have a list of ints: 2: var list = new List<int> { 1, 13, 42, 64, 121, 77, 5, 99, 132 }; 3:  4: // finds index of first even number or -1 if not found. 5: var pos = list.FindIndex(i => i % 2 == 0);   Problem: Finding an item’s index in IEnumerable<T> is not so easy... This is all well and good for lists, but what if we want to do the same thing for IEnumerable<T>?  A collection of IEnumerable<T> has no indexing, so there’s no direct method to find an item’s index.  LINQ, as powerful as it is, gives us many tools to get us this information, but not in one step.  As with almost any problem involving collections, there are several ways to accomplish the same goal.  And once again as with almost any problem involving collections, the choice of the solution somewhat depends on the situation. So let’s look at a few possible alternatives.  I’m going to express each of these as extension methods for simplicity and consistency. Solution: The TakeWhile() and Count() combo One of the things you can do is to perform a TakeWhile() on the list as long as your find condition is not true, and then do a Count() of the items it took.  The only downside to this method is that if the item is not in the list, the index will be the full Count() of items, and not –1.  So if you don’t know the size of the list beforehand, this can be confusing. 1: // a collection of extra extension methods off IEnumerable<T> 2: public static class EnumerableExtensions 3: { 4: // Finds an item in the collection, similar to List<T>.FindIndex() 5: public static int FindIndex<T>(this IEnumerable<T> list, Predicate<T> finder) 6: { 7: // note if item not found, result is length and not -1! 8: return list.TakeWhile(i => !finder(i)).Count(); 9: } 10: } Personally, I don’t like switching the paradigm of not found away from –1, so this is one of my least favorites.  Solution: Select with index Many people don’t realize that there is an alternative form of the LINQ Select() method that will provide you an index of the item being selected: 1: list.Select( (item,index) => do something here with the item and/or index... ) This can come in handy, but must be treated with care.  This is because the index provided is only as pertains to the result of previous operations (if any).  For example: 1: // assume have a list of ints: 2: var list = new List<int> { 1, 13, 42, 64, 121, 77, 5, 99, 132 }; 3:  4: // you'd hope this would give you the indexes of the even numbers 5: // which would be 2, 3, 8, but in reality it gives you 0, 1, 2 6: list.Where(item => item % 2 == 0).Select((item,index) => index); The reason the example gives you the collection { 0, 1, 2 } is because the where clause passes over any items that are odd, and therefore only the even items are given to the select and only they are given indexes. Conversely, we can’t select the index and then test the item in a Where() clause, because then the Where() clause would be operating on the index and not the item! So, what we have to do is to select the item and index and put them together in an anonymous type.  It looks ugly, but it works: 1: // extensions defined on IEnumerable<T> 2: public static class EnumerableExtensions 3: { 4: // finds an item in a collection, similar to List<T>.FindIndex() 5: public static int FindIndex<T>(this IEnumerable<T> list, Predicate<T> finder) 6: { 7: // if you don't name the anonymous properties they are the variable names 8: return list.Select((item, index) => new { item, index }) 9: .Where(p => finder(p.item)) 10: .Select(p => p.index + 1) 11: .FirstOrDefault() - 1; 12: } 13: }     So let’s look at this, because i know it’s convoluted: First Select() joins the items and their indexes into an anonymous type. Where() filters that list to only the ones matching the predicate. Second Select() picks the index of the matches and adds 1 – this is to distinguish between not found and first item. FirstOrDefault() returns the first item found from the previous clauses or default (zero) if not found. Subtract one so that not found (zero) will be –1, and first item (one) will be zero. The bad thing is, this is ugly as hell and creates anonymous objects for each item tested until it finds the match.  This concerns me a bit but we’ll defer judgment until compare the relative performances below. Solution: Convert ToList() and use FindIndex() This solution is easy enough.  We know any IEnumerable<T> can be converted to List<T> using the LINQ extension method ToList(), so we can easily convert the collection to a list and then just use the FindIndex() method baked into List<T>. 1: // a collection of extension methods for IEnumerable<T> 2: public static class EnumerableExtensions 3: { 4: // find the index of an item in the collection similar to List<T>.FindIndex() 5: public static int FindIndex<T>(this IEnumerable<T> list, Predicate<T> finder) 6: { 7: return list.ToList().FindIndex(finder); 8: } 9: } This solution is simplicity itself!  It is very concise and elegant and you need not worry about anyone misinterpreting what it’s trying to do (as opposed to the more convoluted LINQ methods above). But the main thing I’m concerned about here is the performance hit to allocate the List<T> in the ToList() call, but once again we’ll explore that in a second. Solution: Roll your own FindIndex() for IEnumerable<T> Of course, you can always roll your own FindIndex() method for IEnumerable<T>.  It would be a very simple for loop which scans for the item and counts as it goes.  There’s many ways to do this, but one such way might look like: 1: // extension methods for IEnumerable<T> 2: public static class EnumerableExtensions 3: { 4: // Finds an item matching a predicate in the enumeration, much like List<T>.FindIndex() 5: public static int FindIndex<T>(this IEnumerable<T> list, Predicate<T> finder) 6: { 7: int index = 0; 8: foreach (var item in list) 9: { 10: if (finder(item)) 11: { 12: return index; 13: } 14:  15: index++; 16: } 17:  18: return -1; 19: } 20: } Well, it’s not quite simplicity, and those less familiar with LINQ may prefer it since it doesn’t include all of the lambdas and behind the scenes iterators that come with deferred execution.  But does having this long, blown out method really gain us much in performance? Comparison of Proposed Solutions So we’ve now seen four solutions, let’s analyze their collective performance.  I took each of the four methods described above and run them over 100,000 iterations of lists of size 10, 100, 1000, and 10000 and here’s the performance results.  Then I looked for targets at the begining of the list (best case), middle of the list (the average case) and not in the list (worst case as must scan all of the list). Each of the times below is the average time in milliseconds for one execution as computer over the 100,000 iterations: Searches Matching First Item (Best Case)   10 100 1000 10000 TakeWhile 0.0003 0.0003 0.0003 0.0003 Select 0.0005 0.0005 0.0005 0.0005 ToList 0.0002 0.0003 0.0013 0.0121 Manual 0.0001 0.0001 0.0001 0.0001   Searches Matching Middle Item (Average Case)   10 100 1000 10000 TakeWhile 0.0004 0.0020 0.0191 0.1889 Select 0.0008 0.0042 0.0387 0.3802 ToList 0.0002 0.0007 0.0057 0.0562 Manual 0.0002 0.0013 0.0129 0.1255   Searches Where Not Found (Worst Case)   10 100 1000 10000 TakeWhile 0.0006 0.0039 0.0381 0.3770 Select 0.0012 0.0081 0.0758 0.7583 ToList 0.0002 0.0012 0.0100 0.0996 Manual 0.0003 0.0026 0.0253 0.2514   Notice something interesting here, you’d think the “roll your own” loop would be the most efficient, but it only wins when the item is first (or very close to it) regardless of list size.  In almost all other cases though and in particular the average case and worst case, the ToList()/FindIndex() combo wins for performance, even though it is creating some temporary memory to hold the List<T>.  If you examine the algorithm, the reason why is most likely because once it’s in a ToList() form, internally FindIndex() scans the internal array which is much more efficient to iterate over.  Thus, it takes a one time performance hit (not including any GC impact) to create the List<T> but after that the performance is much better. Summary If you’re concerned about too many throw-away objects, you can always roll your own FindIndex() method, but for sheer simplicity and overall performance, using the ToList()/FindIndex() combo performs best on nearly all list sizes in the average and worst cases.    Technorati Tags: C#,.NET,Litte Wonders,BlackRabbitCoder,Software,LINQ,List

    Read the article

  • C#/.NET Little Wonders: The Nullable static class

    - by James Michael Hare
    Once again, in this series of posts I look at the parts of the .NET Framework that may seem trivial, but can help improve your code by making it easier to write and maintain. The index of all my past little wonders posts can be found here. Today we’re going to look at an interesting Little Wonder that can be used to mitigate what could be considered a Little Pitfall.  The Little Wonder we’ll be examining is the System.Nullable static class.  No, not the System.Nullable<T> class, but a static helper class that has one useful method in particular that we will examine… but first, let’s look at the Little Pitfall that makes this wonder so useful. Little Pitfall: Comparing nullable value types using <, >, <=, >= Examine this piece of code, without examining it too deeply, what’s your gut reaction as to the result? 1: int? x = null; 2:  3: if (x < 100) 4: { 5: Console.WriteLine("True, {0} is less than 100.", 6: x.HasValue ? x.ToString() : "null"); 7: } 8: else 9: { 10: Console.WriteLine("False, {0} is NOT less than 100.", 11: x.HasValue ? x.ToString() : "null"); 12: } Your gut would be to say true right?  It would seem to make sense that a null integer is less than the integer constant 100.  But the result is actually false!  The null value is not less than 100 according to the less-than operator. It looks even more outrageous when you consider this also evaluates to false: 1: int? x = null; 2:  3: if (x < int.MaxValue) 4: { 5: // ... 6: } So, are we saying that null is less than every valid int value?  If that were true, null should be less than int.MinValue, right?  Well… no: 1: int? x = null; 2:  3: // um... hold on here, x is NOT less than min value? 4: if (x < int.MinValue) 5: { 6: // ... 7: } So what’s going on here?  If we use greater than instead of less than, we see the same little dilemma: 1: int? x = null; 2:  3: // once again, null is not greater than anything either... 4: if (x > int.MinValue) 5: { 6: // ... 7: } It turns out that four of the comparison operators (<, <=, >, >=) are designed to return false anytime at least one of the arguments is null when comparing System.Nullable wrapped types that expose the comparison operators (short, int, float, double, DateTime, TimeSpan, etc.).  What’s even odder is that even though the two equality operators (== and !=) work correctly, >= and <= have the same issue as < and > and return false if both System.Nullable wrapped operator comparable types are null! 1: DateTime? x = null; 2: DateTime? y = null; 3:  4: if (x <= y) 5: { 6: Console.WriteLine("You'd think this is true, since both are null, but it's not."); 7: } 8: else 9: { 10: Console.WriteLine("It's false because <=, <, >, >= don't work on null."); 11: } To make matters even more confusing, take for example your usual check to see if something is less than, greater to, or equal: 1: int? x = null; 2: int? y = 100; 3:  4: if (x < y) 5: { 6: Console.WriteLine("X is less than Y"); 7: } 8: else if (x > y) 9: { 10: Console.WriteLine("X is greater than Y"); 11: } 12: else 13: { 14: // We fall into the "equals" assumption, but clearly null != 100! 15: Console.WriteLine("X is equal to Y"); 16: } Yes, this code outputs “X is equal to Y” because both the less-than and greater-than operators return false when a Nullable wrapped operator comparable type is null.  This violates a lot of our assumptions because we assume is something is not less than something, and it’s not greater than something, it must be equal.  So keep in mind, that the only two comparison operators that work on Nullable wrapped types where at least one is null are the equals (==) and not equals (!=) operators: 1: int? x = null; 2: int? y = 100; 3:  4: if (x == y) 5: { 6: Console.WriteLine("False, x is null, y is not."); 7: } 8:  9: if (x != y) 10: { 11: Console.WriteLine("True, x is null, y is not."); 12: } Solution: The Nullable static class So we’ve seen that <, <=, >, and >= have some interesting and perhaps unexpected behaviors that can trip up a novice developer who isn’t expecting the kinks that System.Nullable<T> types with comparison operators can throw.  How can we easily mitigate this? Well, obviously, you could do null checks before each check, but that starts to get ugly: 1: if (x.HasValue) 2: { 3: if (y.HasValue) 4: { 5: if (x < y) 6: { 7: Console.WriteLine("x < y"); 8: } 9: else if (x > y) 10: { 11: Console.WriteLine("x > y"); 12: } 13: else 14: { 15: Console.WriteLine("x == y"); 16: } 17: } 18: else 19: { 20: Console.WriteLine("x > y because y is null and x isn't"); 21: } 22: } 23: else if (y.HasValue) 24: { 25: Console.WriteLine("x < y because x is null and y isn't"); 26: } 27: else 28: { 29: Console.WriteLine("x == y because both are null"); 30: } Yes, we could probably simplify this logic a bit, but it’s still horrendous!  So what do we do if we want to consider null less than everything and be able to properly compare Nullable<T> wrapped value types? The key is the System.Nullable static class.  This class is a companion class to the System.Nullable<T> class and allows you to use a few helper methods for Nullable<T> wrapped types, including a static Compare<T>() method of the. What’s so big about the static Compare<T>() method?  It implements an IComparer compatible comparison on Nullable<T> types.  Why do we care?  Well, if you look at the MSDN description for how IComparer works, you’ll read: Comparing null with any type is allowed and does not generate an exception when using IComparable. When sorting, null is considered to be less than any other object. This is what we probably want!  We want null to be less than everything!  So now we can change our logic to use the Nullable.Compare<T>() static method: 1: int? x = null; 2: int? y = 100; 3:  4: if (Nullable.Compare(x, y) < 0) 5: { 6: // Yes! x is null, y is not, so x is less than y according to Compare(). 7: Console.WriteLine("x < y"); 8: } 9: else if (Nullable.Compare(x, y) > 0) 10: { 11: Console.WriteLine("x > y"); 12: } 13: else 14: { 15: Console.WriteLine("x == y"); 16: } Summary So, when doing math comparisons between two numeric values where one of them may be a null Nullable<T>, consider using the System.Nullable.Compare<T>() method instead of the comparison operators.  It will treat null less than any value, and will avoid logic consistency problems when relying on < returning false to indicate >= is true and so on. Tweet   Technorati Tags: C#,C-Sharp,.NET,Little Wonders,Little Pitfalls,Nulalble

    Read the article

  • C#/.NET Little Wonders: Skip() and Take()

    - by James Michael Hare
    Once again, in this series of posts I look at the parts of the .NET Framework that may seem trivial, but can help improve your code by making it easier to write and maintain. The index of all my past little wonders posts can be found here. I’ve covered many valuable methods from System.Linq class library before, so you already know it’s packed with extension-method goodness.  Today I’d like to cover two small families I’ve neglected to mention before: Skip() and Take().  While these methods seem so simple, they are an easy way to create sub-sequences for IEnumerable<T>, much the way GetRange() creates sub-lists for List<T>. Skip() and SkipWhile() The Skip() family of methods is used to ignore items in a sequence until either a certain number are passed, or until a certain condition becomes false.  This makes the methods great for starting a sequence at a point possibly other than the first item of the original sequence.   The Skip() family of methods contains the following methods (shown below in extension method syntax): Skip(int count) Ignores the specified number of items and returns a sequence starting at the item after the last skipped item (if any).  SkipWhile(Func<T, bool> predicate) Ignores items as long as the predicate returns true and returns a sequence starting with the first item to invalidate the predicate (if any).  SkipWhile(Func<T, int, bool> predicate) Same as above, but passes not only the item itself to the predicate, but also the index of the item.  For example: 1: var list = new[] { 3.14, 2.72, 42.0, 9.9, 13.0, 101.0 }; 2:  3: // sequence contains { 2.72, 42.0, 9.9, 13.0, 101.0 } 4: var afterSecond = list.Skip(1); 5: Console.WriteLine(string.Join(", ", afterSecond)); 6:  7: // sequence contains { 42.0, 9.9, 13.0, 101.0 } 8: var afterFirstDoubleDigit = list.SkipWhile(v => v < 10.0); 9: Console.WriteLine(string.Join(", ", afterFirstDoubleDigit)); Note that the SkipWhile() stops skipping at the first item that returns false and returns from there to the rest of the sequence, even if further items in that sequence also would satisfy the predicate (otherwise, you’d probably be using Where() instead, of course). If you do use the form of SkipWhile() which also passes an index into the predicate, then you should keep in mind that this is the index of the item in the sequence you are calling SkipWhile() from, not the index in the original collection.  That is, consider the following: 1: var list = new[] { 1.0, 1.1, 1.2, 2.2, 2.3, 2.4 }; 2:  3: // Get all items < 10, then 4: var whatAmI = list 5: .Skip(2) 6: .SkipWhile((i, x) => i > x); For this example the result above is 2.4, and not 1.2, 2.2, 2.3, 2.4 as some might expect.  The key is knowing what the index is that’s passed to the predicate in SkipWhile().  In the code above, because Skip(2) skips 1.0 and 1.1, the sequence passed to SkipWhile() begins at 1.2 and thus it considers the “index” of 1.2 to be 0 and not 2.  This same logic applies when using any of the extension methods that have an overload that allows you to pass an index into the delegate, such as SkipWhile(), TakeWhile(), Select(), Where(), etc.  It should also be noted, that it’s fine to Skip() more items than exist in the sequence (an empty sequence is the result), or even to Skip(0) which results in the full sequence.  So why would it ever be useful to return Skip(0) deliberately?  One reason might be to return a List<T> as an immutable sequence.  Consider this class: 1: public class MyClass 2: { 3: private List<int> _myList = new List<int>(); 4:  5: // works on surface, but one can cast back to List<int> and mutate the original... 6: public IEnumerable<int> OneWay 7: { 8: get { return _myList; } 9: } 10:  11: // works, but still has Add() etc which throw at runtime if accidentally called 12: public ReadOnlyCollection<int> AnotherWay 13: { 14: get { return new ReadOnlyCollection<int>(_myList); } 15: } 16:  17: // immutable, can't be cast back to List<int>, doesn't have methods that throw at runtime 18: public IEnumerable<int> YetAnotherWay 19: { 20: get { return _myList.Skip(0); } 21: } 22: } This code snippet shows three (among many) ways to return an internal sequence in varying levels of immutability.  Obviously if you just try to return as IEnumerable<T> without doing anything more, there’s always the danger the caller could cast back to List<T> and mutate your internal structure.  You could also return a ReadOnlyCollection<T>, but this still has the mutating methods, they just throw at runtime when called instead of giving compiler errors.  Finally, you can return the internal list as a sequence using Skip(0) which skips no items and just runs an iterator through the list.  The result is an iterator, which cannot be cast back to List<T>.  Of course, there’s many ways to do this (including just cloning the list, etc.) but the point is it illustrates a potential use of using an explicit Skip(0). Take() and TakeWhile() The Take() and TakeWhile() methods can be though of as somewhat of the inverse of Skip() and SkipWhile().  That is, while Skip() ignores the first X items and returns the rest, Take() returns a sequence of the first X items and ignores the rest.  Since they are somewhat of an inverse of each other, it makes sense that their calling signatures are identical (beyond the method name obviously): Take(int count) Returns a sequence containing up to the specified number of items. Anything after the count is ignored. TakeWhile(Func<T, bool> predicate) Returns a sequence containing items as long as the predicate returns true.  Anything from the point the predicate returns false and beyond is ignored. TakeWhile(Func<T, int, bool> predicate) Same as above, but passes not only the item itself to the predicate, but also the index of the item. So, for example, we could do the following: 1: var list = new[] { 1.0, 1.1, 1.2, 2.2, 2.3, 2.4 }; 2:  3: // sequence contains 1.0 and 1.1 4: var firstTwo = list.Take(2); 5:  6: // sequence contains 1.0, 1.1, 1.2 7: var underTwo = list.TakeWhile(i => i < 2.0); The same considerations for SkipWhile() with index apply to TakeWhile() with index, of course.  Using Skip() and Take() for sub-sequences A few weeks back, I talked about The List<T> Range Methods and showed how they could be used to get a sub-list of a List<T>.  This works well if you’re dealing with List<T>, or don’t mind converting to List<T>.  But if you have a simple IEnumerable<T> sequence and want to get a sub-sequence, you can also use Skip() and Take() to much the same effect: 1: var list = new List<double> { 1.0, 1.1, 1.2, 2.2, 2.3, 2.4 }; 2:  3: // results in List<T> containing { 1.2, 2.2, 2.3 } 4: var subList = list.GetRange(2, 3); 5:  6: // results in sequence containing { 1.2, 2.2, 2.3 } 7: var subSequence = list.Skip(2).Take(3); I say “much the same effect” because there are some differences.  First of all GetRange() will throw if the starting index or the count are greater than the number of items in the list, but Skip() and Take() do not.  Also GetRange() is a method off of List<T>, thus it can use direct indexing to get to the items much more efficiently, whereas Skip() and Take() operate on sequences and may actually have to walk through the items they skip to create the resulting sequence.  So each has their pros and cons.  My general rule of thumb is if I’m already working with a List<T> I’ll use GetRange(), but for any plain IEnumerable<T> sequence I’ll tend to prefer Skip() and Take() instead. Summary The Skip() and Take() families of LINQ extension methods are handy for producing sub-sequences from any IEnumerable<T> sequence.  Skip() will ignore the specified number of items and return the rest of the sequence, whereas Take() will return the specified number of items and ignore the rest of the sequence.  Similarly, the SkipWhile() and TakeWhile() methods can be used to skip or take items, respectively, until a given predicate returns false.    Technorati Tags: C#, CSharp, .NET, LINQ, IEnumerable<T>, Skip, Take, SkipWhile, TakeWhile

    Read the article

< Previous Page | 23 24 25 26 27 28 29 30 31 32 33 34  | Next Page >