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  • Why do I get this Debug Assertion Failed? Expression: list iterator not dereferenceable [migrated]

    - by Karel
    I'm trying this example in the (translated to dutch) book of Bjarne Stroustrup (C++): #include <vector> #include <list> #include "complex.h" complex ac[200]; std::vector<complex> vc; std::list<complex> l; template<class In, class Out> void Copy(In from, In too_far, Out to) { while(from != too_far) { *to = *from; ++to; ++from; } } void g(std::vector<complex>& vc , std::list<complex>& lc) { Copy(&ac[0], &ac[200], lc.begin()); // generates debug error Copy(lc.begin(), lc.end(), vc.begin()); // also generates debug error } void f() { ac[0] = complex(10,20); g(vc, l); } int main () { f(); } ** Compiling and Linking goes successful (0 errors/warnings)** But at runtime I get this error: Debug Assertion Failed! Program: path to exe file: \program files\ms vs studio 10.0\vc\include\list Line: 207 Expression: list iterator not dereferenceable For information on how your program can cause an assertion failure, see the Visual C++ documentation on asserts. (Press retry to debug the application)

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  • Do you store mysql exports in your version control tool for reverting to in event of error?

    - by Rob
    We run an internal web server with in-house software to run a manufacturing line. When new product features are to be added, either or both of the following occur: changes to the in-house server software may be required to support these - these are for significant changes in functionality, being code drive. changes to the MySQL database for new entries for the part numbers, these are for smaller changes, configurations, changes to already existing values and parameters -- such changes don't require code changes. Ideally we'd want our changes to be here rather than in item 1. Item 1 is version controlled in Subversion, so previous revisions can be referred to for rolling back to in the event of problems introduced in the latest revision. But what about changes to the MySQL database? We have quality processes to ensure that such changes are error-free but there is always a chance that errors can pass through, e.g. mistake in data entry or faults with the code that uses the MySQL corrupting the database etc. We have a automated backup every 6 hours but what if we want more manual defined checkpoints in between these intervals, we could use the same backup system but I wondered if folks here used other methods to store previous states of databases, e.g. exporting the database as a plain text SQL dump -- at least with this method it would be possible to see diffs e.g. in Beyond Compare for trouble shooting. Thoughts?

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  • Starting out with OpenGL when most tutorials are out of date

    - by AUTO
    I'm sure there are already a bunch of questions like this asked, but the constant updating of the OpenGL library throws them all away, and in a month or two, the answers here will be worthless again. I am ready to start programming in OpenGL using C++. I've got a working compiler (DevCpp; do NOT ask me to switch to VC++, and don't ask me why). Now I'm just looking for a solid tutorial on how to program with OpenGL. My assistant found the tutorial provided by NeHe Productions, but as I've come to find out, it's WAY OUT OF DATE! (although I did pull together a basic window to support an OpenGL canvas) Then I went online, and found the OpenGL SuperBible, which apparently uses freeglut? But what I'd like to know is whether or not SuperBible 5th edition is up to date any longer. The suggestion to freeglut I found said the latest version was 2.6.0 but now it's 2.8.0! Is the OpenGL SuperBible still a good, and fairly up-to-date place to start? Is there a better place to go to learn OpenGL? Am I allowed to simply store freeglut in the DevCpp include directory (maybe in GL), or is there some important procedure? Are there any comments or suggestions that I didn't think to ask since I'm only just beginning? @dreta cleared some things up for me, so now I have a better idea of what to ask: I think I'd like to start out with OpenGL using a wrapper library instead of directly accessing OpenGL.I just think that, for a beginner, it would be easier for me to program and get good results, while I don't yet have to understand all the grimy details (as @stephelton mentioned). The problem is, I can't find any library that doesn't have undefined references to no longer supported functions. Freeglut sounds operational, but it still uses GLU.Does anyone know what I can do?Also, I tried compiling the first SuperBible's source, but I got errors since GLAPI is not being defined as a type, the error originating in the GLU library. I'd like to use the SuperBible, but I don't know how to fix this.

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  • CodeStock 2012 Review: Eric Landes( @ericlandes ) - Automated Tests in to automated Builds! How to put the right type of automated tests in to the right automated builds.

    Automated Tests in to automated Builds! How to put the right type of automated tests in to the right automated builds.Speaker: Eric LandesTwitter: @ericlandesBlog: http://ericlandes.com/ This was one of the first sessions I attended during CodeStock 2012. Eric’s talk focused mostly on unit testing, and that the lack of proper unit testing can be compared to stealing from an employer. His point was that if you’re not doing proper unit testing then all of the time wasted on fixing issues that could have been detected with unit tests is like stealing money from employer. He makes the assumption that that time spent on fixing these issues could have been better spent developing new features that drive the business. To a point I can agree with Eric’s argument regarding unit testing and stealing from a company’s perspective. I can see how he relates resources being shifted from new development to bug fixes as stealing based on the fact that the resources used to fix bugs are directly taken from other projects. He also states that Boring/Redundant and Build/Test tasks should be automated because it reduces the changes of errors and frees up developer to do what they do best, DEVELOP! When he refers to testing, he breaks testing down in to four distinct types. Unit Test Acceptance Test (This also includes Integration Tests) Performance Test UI Test With this he also recommends that developers should not go buck wild striving for 100% code coverage because some test my not provide a great return on investment. In his experience he recommends that 70% test coverage was a very acceptable rate.

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  • looking for a short explanation of fuzzy logic

    - by user613326
    Well i got the idea that basics of fuzzy logic are not that hard to grasp. And i got the feeling that someone might explain it to me in like 30 minutes. Just like i understand neural networks and am able to re-create the famous Xor problem. And go just beyond it and create 3 layer networks of x nodes. I'd like to understand fuzzy till a similar usefully level, in c# language. However the problem is face, I'd like to get concept right however i see many websites who include lots of errors in their basic explaining. Like for example showing pictures and use different numbers as shown in pictures to calculate, as if lots of people just copied stuff without noticing what they write down. While others for me go to deep in their math notation) To me that's very annoying to learn from. For me there is no need to re-invent wheel; Aforge already got a fuzzy logic framework. So what i am looking for are some good examples, good examples like how the neural XOR problem is solved. Is there anyone such a instructional resource out there; do you know a web page, or YouTube where it is shortly explained, what would you recommend me ? Note this article comes close; but it just doesnt nail it for me. After that i downloaded a bunch of free PDF's but most are academic and hard to read for me (i'm not English and dont have a special math degree). (i've been looking around a lot for this, good starter material about it is hard to find).

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  • Removed Java replaced with newest "Sun Java", disc won't boot, and won't let me re-install grub using boot repair disc

    - by Al Rowe
    Had a minor problem with my Stock market platform. Set-up screen would freeze program. Called their tech support, got their "Linux guy", who advised remove all Java and replace, not with synaptic version, but newest Sun Java. After removing, computer auto rebooted, and went to blue mem-test screen. Showed no errors, but couldn't get back in. Tried two versions of boot repair disc from iso (checked md5sum, showed good.), but fix aborted, giving apt-error detected. Opened a terminal and typed (or copy/paste): sudo chroot "/mnt/boot-sav/sda1" apt-get -f install. My system is Ubuntu 12.04. Had a few very minor issues from install, all fixed. Also added some of my favorite gnome tricks just to make life easier, but none that could have caused this. Added script to add shortcuts to desktop, open terminal in any menu from inside it, access root terminal, etc. System was firewalled and using avast antivirus (o.k., I'm paranoid. Used to do Windows sys-op and security.) But relative newbie to Linux.

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  • Cannot Restore GRUB (Ubuntu 11.04 + Win 7)

    - by Benny
    I'm trying to fix GRUB on my PC, but I'm running into serious issues doing so. Any help would be greatly appreciated as I'm completely crippled right now. Here is the sequence of events for this PC: Installed Windows 7 Split full disk into two partitions (one for win7 and one for multimedia) Long time passed Split one of the partitions into two again Installed Ubuntu 11.04 on new partition A little time passed Windows 7 acting up, reinstall Ubuntu GRUB gone Tried restoring GRUB by mounting and grub-install from live USB Tried switching to a live CD instead of USB (thinking it might be the drive) Now I don't see GRUB and I'm getting "input/output" errors An example i/o error: ubuntu@ubuntu:~$ sudo fdisk -l Disk /dev/sda: 750.2 GB, 750156374016 bytes 255 heads, 63 sectors/track, 91201 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0xbe86aff6 Device Boot Start End Blocks Id System /dev/sda1 * 1 48727 391393280 7 HPFS/NTFS /dev/sda2 48727 77063 227612647+ 7 HPFS/NTFS /dev/sda3 77063 91202 113566721 5 Extended /dev/sda5 77063 90622 108908544 83 Linux /dev/sda6 90622 91202 4657152 82 Linux swap / Solaris ubuntu@ubuntu:~$ sudo mount /dev/sda5 /mnt ubuntu@ubuntu:~$ sudo grub-install --root-directory=/mnt /dev/sda mkdir: cannot create directory `/mnt/boot': Input/output error ubuntu@ubuntu:~$ cd /mnt ubuntu@ubuntu:/mnt$ ls ls: cannot access etc: Input/output error

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  • Ubuntu 12.04 upgrade and thunderbird

    - by Dcm1405
    After applying the suggested updates (179) an error message at the very end of the process suggested me to run apt-get install -f. Since it is a fairly new Ubuntu install (x86) I didn't setup anything in Thunderbird yet. Different error messages (see details) were generated with the -f process: ~$ sudo apt-get install -f Reading package lists... Done Building dependency tree Reading state information... Done Correcting dependencies... Done The following extra packages will be installed: thunderbird Suggested packages: latex-xft-fonts The following packages will be upgraded: thunderbird 1 upgraded, 0 newly installed, 0 to remove and 0 not upgraded. 2 not fully installed or removed. Need to get 0 B/20.8 MB of archives. After this operation, 594 kB of additional disk space will be used. Do you want to continue [Y/n]? y (Reading database ... 170457 files and directories currently installed.) Preparing to replace thunderbird 11.0.1+build1-0ubuntu2 (using .../thunderbird_12.0.1+build1-0ubuntu0.12.04.1_i386.deb) ... Unpacking replacement thunderbird ... dpkg-deb (subprocess): data: internal gzip read error: '<fd:4>: invalid code lengths set' dpkg-deb: error: subprocess <decompress> returned error exit status 2 dpkg: error processing /var/cache/apt/archives /thunderbird_12.0.1+build1-0ubuntu0.12.04.1_i386.deb (--unpack): short read on buffer copy for backend dpkg-deb during `./usr/lib/thunderbird/libxul.so' Errors were encountered while processing: /var/cache/apt/archives/thunderbird_12.0.1+build1-0ubuntu0.12.04.1_i386.deb E: Sub-process /usr/bin/dpkg returned an error code (1)

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  • QapTcha error issue. Works locally, not on live server [migrated]

    - by BlassFemur
    I am adding QapTcha (http://demos.myjqueryplugins.com/qaptcha/) to a website that I am working on and I'm getting the error "Uncaught TypeError: Cannot read property 'error' of null". What's weird to me is everything is working perfectly locally. No errors or anything. Once I uploaded via ftp to the live server, I get the above error. Below is the block of code that seems to be generating the error: Slider.draggable({ revert: function(){ if(opts.autoRevert) { if(parseInt(Slider.css("left")) (bgSlider.width()-Slider.width()-10)) return false; else return true; } }, containment: bgSlider, axis:'x', stop: function(event,ui){ if(ui.position.left (bgSlider.width()-Slider.width()-10)) { // set the SESSION iQaptcha in PHP file $.post(opts.PHPfile,{ action : 'qaptcha', qaptcha_key : inputQapTcha.attr('name') }, function(data) { if(!data.error) Uncaught TypeError: Cannot read property 'error' of null { Slider.draggable('disable').css('cursor','default'); inputQapTcha.val(''); TxtStatus.text(opts.txtUnlock).addClass('dropSuccess').removeClass('dropError'); form.find('input[type=\'submit\']').removeAttr('disabled'); if(opts.autoSubmit) form.find('input[type=\'submit\']').trigger('click'); } },'json'); } } }); I'm not really sure what's going on as to why it works locally and not on the server. Any help/ suggestions would be appreciated. Thanks

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  • I have deleted python files in usr/bin and cant reinstall it

    - by Plonkaa
    I am a novice at Ubuntu and unfortunately i have deleted 3 files in the usr/bin folder python 2.7 python python 2.6 Now my update manager wont work and when i type in python into gnome it says that it is no longer there. Please help me ive tried loads of different things but it just wont work. The closest i got was the following: I typed in sudo apt-get -f install and i thought i had fixed it but then i got a error message - Reading package lists... Done Building dependency tree Reading state information... Done The following packages were automatically installed and are no longer required: gir1.2-folks-0.6 gir1.2-polkit-1.0 libcogl5 mutter-common gir1.2-json-1.0 libcaribou0 gir1.2-accountsservice-1.0 gir1.2-clutter-1.0 gir1.2-gkbd-3.0 gir1.2-networkmanager-1.0 caribou libcogl-common libmutter0 gir1.2-mutter-3.0 gjs gir1.2-caribou-1.0 libclutter-1.0-0 gir1.2-telepathylogger-0.2 libclutter-1.0-common cups-pk-helper gir1.2-upowerglib-1.0 gir1.2-cogl-1.0 libmozjs185-1.0 gir1.2-telepathyglib-0.12 gir1.2-gee-1.0 libgjs0c gnome-shell-common Use 'apt-get autoremove' to remove them. The following extra packages will be installed: ubuntu-sso-client The following packages will be upgraded: ubuntu-sso-client 1 upgraded, 0 newly installed, 0 to remove and 35 not upgraded. 2 not fully installed or removed. Need to get 0 B/57.7 kB of archives. After this operation, 16.4 kB of additional disk space will be used. Do you want to continue [Y/n]? y Setting up python-minimal (2.7.2-7ubuntu2) ... /var/lib/dpkg/info/python-minimal.postinst: 4: python2.7: not found dpkg: error processing python-minimal (--configure): subprocess installed post-installation script returned error exit status 127 Errors were encountered while processing: python-minimal E: Sub-process /usr/bin/dpkg returned an error code (1) any advice is appreciated!

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  • Multiple Denial of Service (DoS) vulnerabilities in FreeType

    - by chandan
    CVE DescriptionCVSSv2 Base ScoreComponentProduct and Resolution CVE-2012-1126 Improper Restriction of Operations within the Bounds of a Memory Buffer vulnerability 10.0 FreeType Font Engine Solaris 11 Contact Support Solaris 10 SPARC: 119812-16 X86: 119813-18 Solaris 9 Contact Support CVE-2012-1127 Improper Restriction of Operations within the Bounds of a Memory Buffer vulnerability 9.3 CVE-2012-1128 Improper Restriction of Operations within the Bounds of a Memory Buffer vulnerability 9.3 CVE-2012-1129 Improper Restriction of Operations within the Bounds of a Memory Buffer vulnerability 9.3 CVE-2012-1130 Improper Restriction of Operations within the Bounds of a Memory Buffer vulnerability 9.3 CVE-2012-1131 Improper Restriction of Operations within the Bounds of a Memory Buffer vulnerability 9.3 CVE-2012-1132 Improper Restriction of Operations within the Bounds of a Memory Buffer vulnerability 9.3 CVE-2012-1133 Improper Restriction of Operations within the Bounds of a Memory Buffer vulnerability 9.3 CVE-2012-1134 Improper Restriction of Operations within the Bounds of a Memory Buffer vulnerability 9.3 CVE-2012-1135 Improper Restriction of Operations within the Bounds of a Memory Buffer vulnerability 9.3 CVE-2012-1136 Improper Restriction of Operations within the Bounds of a Memory Buffer vulnerability 9.3 CVE-2012-1137 Improper Restriction of Operations within the Bounds of a Memory Buffer vulnerability 9.3 CVE-2012-1138 Improper Restriction of Operations within the Bounds of a Memory Buffer vulnerability 9.3 CVE-2012-1139 Improper Restriction of Operations within the Bounds of a Memory Buffer vulnerability 9.3 CVE-2012-1140 Improper Restriction of Operations within the Bounds of a Memory Buffer vulnerability 9.3 CVE-2012-1141 Improper Restriction of Operations within the Bounds of a Memory Buffer vulnerability 9.3 CVE-2012-1142 Improper Restriction of Operations within the Bounds of a Memory Buffer vulnerability 9.3 CVE-2012-1143 Numeric Errors vulnerability 4.3 CVE-2012-1144 Improper Restriction of Operations within the Bounds of a Memory Buffer vulnerability 9.3 This notification describes vulnerabilities fixed in third-party components that are included in Sun's product distribution.Information about vulnerabilities affecting Oracle Sun products can be found on Oracle Critical Patch Updates and Security Alerts page.

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  • After login I only get a terminal window

    - by Ambidex
    First of, let me tell you I'm a n00b at ubuntu. I have updated my Ubuntu mediacenter to a later version of ubuntu, currently at 12.04. I'm working through a lot of updates to get to the latest. But since my first update I got the new login screen (lightdm?) and my autologin wasen't working anymore. So I Googled how I could make lightdm autologin. I've managed this by making my /etc/lightdm/lightdm.conf look as follows: [SeatDefaults] greeter-session=unity-greeter user-session=ubuntu autologin-user=my_user autologin-userutologin-user=-timeout=0 Which seemed to work... But now that it automatically logs in, I seem to get the following type of screen (through nomachine remote desktop client): Sorry... I am unable to post my screenshot here because I do not have the 10 reputation points in askubuntu yet.... darn it... But the screen has a terminal at the top left of the screen (not an actual "window"), and the ubuntu loading screen is still behind it. I've tried running startx as you can see. But, this seems to actually be x server. But if I run unity --reset, it seems that a lot of the desktop gets restored, but... with a lot of errors and warnings and the next time I boot, it's the same story all over again. Also, when I close the terminal window after getting my desktop back, I get thrown back at the login screen. Please bear with my lack of knowledge of ubuntu and it's underlying unix. I thank you in advance.

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  • mdadm: brakes boot due to "is not ready yet or not present" error

    - by BarsMonster
    This is so damn frustrating :-| I've spent like 20 hours on this nice error, and seems like dozens of people over Internet too, and no clear solution yet. I have non-system RAID-5 of 5 disks, and it's fine. But during boot up it says that "/dev/md0 is not ready yet or not present" and asks to press 'S'. Very nice for Ubuntu Server - I have to bring monitor and keyboard to go next. After this system boots and it's all fine. md0 device works, /proc/mdstat is fine. When I do mount -a - it mounts this array without errors and works fine. As a dumb and shameful workaround I added noauto in /etc/fstab, and did mounting in /etc/rc.local - it works fine then. Any hints how to make it work properly? fstab: UUID=3588dfed-47ae-4c32-9855-2d69df713b86 /var/bigfatdisk ext4 noauto,noatime,data=writeback,barrier=0,nobh,commit=5 0 0 mdadm config: It is autogenerated: # mdadm.conf # # Please refer to mdadm.conf(5) for information about this file. # # by default, scan all partitions (/proc/partitions) for MD superblocks. # alternatively, specify devices to scan, using wildcards if desired. DEVICE partitions # auto-create devices with Debian standard permissions CREATE owner=root group=disk mode=0660 auto=yes # automatically tag new arrays as belonging to the local system HOMEHOST <system> # instruct the monitoring daemon where to send mail alerts MAILADDR CENSORED # definitions of existing MD arrays ARRAY /dev/md/0 metadata=1.2 bitmap=/var/md0_intent UUID=efccbeb6:a0a65cd6:470dcdf3:62781188 name=LBox2:0 # This file was auto-generated on Mon, 10 Jan 2011 04:06:55 +0200 # by mkconf 3.1.2-2

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  • DualLayout OpenSourceFood demo site installation instructions

    - by svdoever
    We released DualLayout which enables advanced web design with the power of SharePoint. DualLayout and a demo site can be downloaded from the DualLayout product page. This blogpost contains detailed instructions on installing the demo site. The demo site is based on the site http://opensourcefood.com. The demo site requires internet access because it still links to pages and resources of the real site. Execute the following steps to install the demo site: Copy the OpenSourceFoodDemo.zip file to your SharePoint Server 2010 Make sure that the zip file in “unblocked”, otherwise files are assumed from other computer (right-click on zip file, press “Unblock” button if available) Unzip the OpenSourceFoodDemo.zip to a folder of your choice (c:\OpenSourceFoodDemo) Open the SharePoint  Start->Microsoft SharePoint 2010 Products->SharePoint 2010 Management Shell Change directory to the unzip folder (cd c:\OpenSourceFoodDemo) Start install script: .\InstallDemoSite.ps1 Answer the questions, default values in most cases ok. A little guidance: Question: Give credentials for the account that will be used for the application pool Answer: use for example same account as used for the application pool of your SharePoint site (lookup in IIS Manager) Question: Give credentials for the account that will be used for the application pool Answer: Use same account you are currently logged in with The demo site is made available through a backup and restore. The SharePoint Server 2010 installation must be patched to a level equal or higher to the update level on the SharePoint Server used to create the backup. If you get errors with respect to restore check http://technet.microsoft.com/en-us/sharepoint/ff800847.aspx for downloading the latest cumulative update.

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  • compile error in Ubuntu 10

    - by yozloy
    Hey guys I got a vps which run solusVM. I'm now trying to install ruby 1.9.2 in it. I follow this guide: after I run this command apt-get update apt-get -y install build-essential zlib1g zlib1g-dev libxml2 libxml2-dev libxslt-dev I got this error below root@makserver:/usr/local/src/ruby-1.9.2-p0# apt-get -f install Reading package lists... Done Building dependency tree... Done Correcting dependencies... Done The following extra packages will be installed: libc6 Suggested packages: glibc-doc The following packages will be upgraded: libc6 1 upgraded, 0 newly installed, 0 to remove and 80 not upgraded. Need to get 0B/4252kB of archives. After this operation, 4096B disk space will be freed. Do you want to continue [Y/n]? y debconf: apt-extracttemplates failed: Bad file descriptor (Reading database ... 21594 files and directories currently installed.) Preparing to replace libc6 2.11.1-0ubuntu7.2 (using .../libc6_2.11.1-0ubuntu7.8_amd64.deb) ... open2: fork failed: Cannot allocate memory at /usr/share/perl5/Debconf/ConfModule.pm line 59 dpkg: error processing /var/cache/apt/archives/libc6_2.11.1-0ubuntu7.8_amd64.deb (--unpack): subprocess new pre-installation script returned error exit status 12 Errors were encountered while processing: /var/cache/apt/archives/libc6_2.11.1-0ubuntu7.8_amd64.deb E: Sub-process /usr/bin/dpkg returned an error code (1) Anybody can tell me how can I correct this. Thanks

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  • Video game "Gish" will only launch from command line

    - by aberration
    Platform: Lubuntu 11.10 x64 Program: Gish When I try to launch Gish from the command line (/opt/gish/gi.sh), there are no problems. But when I try to launch it from the LXDE menu, it will not start. Contents of /usr/share/applications/gish.desktop: [Desktop Entry] Categories=Game;ActionGame;AdventureGame;ArcadeGame; Exec=/opt/gish/gi.sh Path=/opt/gish Icon=x-gish Terminal=false Type=Application Name=Gish I tried changing Terminal=false to Terminal=true to debug it, but then I just got a blank terminal, and the game didn't start. Edit: Here is some additional information, as requested by Eliah Kagan below: I tried editing /usr/share/applications/gish.desktop, as recommended, but it had no effect However, ~/.xsession-errors contained the following error: [: 8: x86_64: unexpected operator ./gish_32: error while loading shared libraries: libGL.so.1: wrong ELF class: ELFCLASS64 I think there's a problem with the /opt/gish/gi.sh shell script. This is its contents: cd /opt/gish/ MACHINE_TYPE=`uname -m` if [ ${MACHINE_TYPE} == 'x86_64' ]; then ./gish_64 else ./gish_32 fi I'm not too familiar with Bash, so hopefully someone else can point out the error. I have a 64-bit machine. I think that when the script is run from the command line, it's properly launching the 64-bit version (/opt/gish/gish_64), but when it's run from the LXDE menu, it's launching the 32-bit version (/opt/gish/gish_32), which is causing the libGL.so.1 error. However, this may be related to my libGL.so.1 problems with 2 other games.

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  • Does immutability entirely eliminate the need for locks in multi-processor programming?

    - by GlenPeterson
    Part 1 Clearly Immutability minimizes the need for locks in multi-processor programming, but does it eliminate that need, or are there instances where immutability alone is not enough? It seems to me that you can only defer processing and encapsulate state so long before most programs have to actually DO something. If a program performs actions on multiple processors, something needs to collect and aggregate the results. All this involves multi-process communication before, after, and possibly during some transformations. The start and end state of the machines are different. Can this always be done with no locks just by throwing out each object and creating a new one instead of changing the original (a crude view of immutability)? What cases still require locking? I'm interested in both the theoretical/academic answer and the practical/real-world answer. I know a lot of functional programmers like to talk about "no side effect" but in the "real world" everything has a side effect. Every processor click takes time and electricity and machine resources away from other processes. So I understand that there may be more than one perspective to answer this question from. If immutability is safe, given certain bounds or assumptions, I want to know what the borders of the "safety zone" are exactly. Some examples of possible boundaries: I/O Exceptions/errors Interfaces with programs written in other languages Interfaces with other machines (physical, virtual, or theoretical) Special thanks to @JimmaHoffa for his comment which started this question! Part 2 Multi-processor programming is often used as an optimization technique - to make some code run faster. When is it faster to use locks vs. immutable objects? Given the limits set out in Amdahl's Law, when can you achieve better over-all performance (with or without the garbage collector taken into account) with immutable objects vs. locking mutable ones? Summary I'm combining these two questions into one to try to get at where the bounding box is for Immutability as a solution to threading problems.

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  • Program instantly closing [migrated]

    - by Ben Clayton
    I made this program and when I compiled it there were no errors but the program just instantly closed, any answers would be appreciated. #include <iostream> //Main commands #include <string> // String commands #include <windows.h> // Sleep using namespace std; int main () { //Declaring variables float a; bool end; std::string input; end = false; // Making sure program doesn't end instantly cout << "Enter start then the number you want to count down from." << ".\n"; while (end = false){ cin >> input; cout << ".\n"; if (input.find("end") != std::string::npos) // Ends the program if user types end end = true; else if (input.find("start" || /* || is or operator*/ "restart") != std::string::npos) // Sets up the countdown timer if the user types start { cin >> a; cout << ".\n"; while (a>0){ Sleep(100); a = a - 0.1; cout << a << ".\n"; } cout << "Finished! Enter restart and then another number, or enter end to close the program" << ".\n"; } else // Tells user to start program cout << "Enter start"; } return 0; // Ends program when (end = true) }

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  • Thinking skills to be a good programmer

    - by Paul
    I have been programming for last 15 years with non-CS degree. Main reason I got into programming was that I liked to learn new things and apply them to my work. And I was able to find and fix programming errors and their causes faster than others. But I never find myself a a guru or an expert, maybe due to my non-CS major. And when I saw great programmers, I observed they are very good, much better than me of course, at solving problems. One skill I found good in my mid-career is thinking of requirements and tasks in a reverse order and in abstract. In that way, I can see what is really required for me to do without detail and can quickly find parts of solution that already exist. So I wonder if there are other thinking skills to be a good programmer. I've followed Q&As below and actually read some of books recommended there. But I couldn't really pickup good methods directly applicable for my programming work. What non-programming books should a programmer read to help develop programming/thinking skills? Skills and habits to develop to be good at programming (I'm a newbie)

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  • apt-get issue after upgrading to 12.04

    - by user83906
    I have recently upgraded my cluster from 11.10 to 12.04. After the upgrade, I am having trouble running apt-get on the cluster nodes. I can ssh between the nodes (client-to-client; client-to-head; client-to-external etc.). However, sudo apt-get update produces the following errors: Ign http://us.archive.ubuntu.com precise InRelease Ign http://security.ubuntu.com precise-security InRelease Ign http://www.openfoam.org maverick InRelease Ign http://us.archive.ubuntu.com precise-updates InRelease Err http://security.ubuntu.com precise-security Release.gpg Something wicked happened resolving 'security.ubuntu.com:http' (-5 - No address associated with hostname) Err http://www.openfoam.org maverick Release.gpg Something wicked happened resolving 'www.openfoam.org:http' (-5 - No address associated with hostname) Ign http://us.archive.ubuntu.com precise-backports InRelease Ign http://www.openfoam.org maverick Release Ign http://security.ubuntu.com precise-security Release Err http://us.archive.ubuntu.com precise Release.gpg Something wicked happened resolving 'us.archive.ubuntu.com:http' (-5 - No address associated with hostname) Ign http://security.ubuntu.com precise-security/main Sources/DiffIndex Err http://us.archive.ubuntu.com precise-updates Release.gpg Something wicked happened resolving 'us.archive.ubuntu.com:http' (-5 - No address associated with hostname) Ign http://security.ubuntu.com precise-security/restricted Sources/DiffIndex 15% [Connecting to us.archive.ubuntu.com] [Connecting to security.ubuntu.com] [Connecting to www.openfoam.org] On the headnode, I have in /etc/network/iterfaces: auto eth0 iface eth0 inet static address 192.168.0.1/24 On the client nodes, I have /etc/network/iterfaces: auto eth0 iface eth0 inet static address 192.168.0.101 netmask 255.255.255.0 gateway 192.168.0.1 Please advise.

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  • Why do I always get this error when using 'apt-get' commands?

    - by Venki
    I am using Ubuntu 14.04(with Unity). Just today(as of the date of this post) I did a sudo apt-get update && sudo apt-get upgrade and at the end of the 'Upgrade' process I got the following error :- Setting up crossplatformui (1.0.38) ... * Stopping ACPI services... [ OK ] * Starting ACPI services... [ OK ] package libqtgui4 exist QT_VERSION = 4 make -C /lib/modules/3.13.0-27-generic/build M=/usr/local/bin/ztemtApp/zteusbserial/below2.6.27 modules make[1]: Entering directory `/usr/src/linux-headers-3.13.0-27-generic' CC [M] /usr/local/bin/ztemtApp/zteusbserial/below2.6.27/usb-serial.o /usr/local/bin/ztemtApp/zteusbserial/below2.6.27/usb-serial.c:34:28: fatal error: linux/smp_lock.h: No such file or directory #include <linux/smp_lock.h> ^ compilation terminated. make[2]: *** [/usr/local/bin/ztemtApp/zteusbserial/below2.6.27/usb-serial.o] Error 1 make[1]: *** [_module_/usr/local/bin/ztemtApp/zteusbserial/below2.6.27] Error 2 make[1]: Leaving directory `/usr/src/linux-headers-3.13.0-27-generic' make: *** [modules] Error 2 dpkg: error processing package crossplatformui (--configure): subprocess installed post-installation script returned error exit status 2 Errors were encountered while processing: crossplatformui E: Sub-process /usr/bin/dpkg returned an error code (1) From then on whatever apt-get command I use(so far as I know, except apt-get update) I keep getting the above error at the end of the process. But whichever apt-get command I use does what it has to without fail.(For example I tried installing blender with sudo apt-get install blender and it installed fine though it showed the above error.) After this I even got a kernel update(from 3.13.0-27 to 3.13.0-29 via the Software Updater), but even now the issue persists. How do I solve this issue?

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  • apt-cacher ng / upgrade fails from client

    - by todayis23
    I'm running apt-cacher ng on an Ubuntu Hardy server and try to upgrade the packages on a Natty client (which was initially a Maverick). I didn't do anything on the server. On the client I tried two setups. I configure APT to use a http-proxy. On the client I did a "apt-get update" which worked fine, but very slowly. In the acng-report.html I see an entry, which seems to be correct. After verifying Install these packages without verification [y/N]? y "apt-get upgrade" failes with the message: Err http://archive.ubuntu.com/ubuntu/ natty-updates/main libnux-0.9-common all 0.9.48-0ubuntu1.1 503 Name or service not known The GUI update manager fails as well with the message, that untrusted packages will be installed. I edit sources.list and add the server in the correct format to all sources. "apt-get update" is very slowly... and I get a lot of errors like this: W: Failed to fetch http://[::ffff:10.10.10.10]:3142/archive.ubuntu.com/ubuntu/dists/natty/main/binary-i386/Packages 403 Forbidden file type or location After that "apt-get upgrade" says: 0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded. What could be wrong? Is it possible to use apt-cacher ng on an older system for upgrading newer systems? Thank you in advance!

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  • How is software used in critical life-or-death systems tested?

    - by waiwai933
    An airplane, as opposed to, for example, a website, is a system where any failure in certain systems is completely unacceptable, since errors in e.g. flight monitoring can cause the autopilot to malfunction and do a dive. Obviously, this doesn't happen since the brilliant engineers at Boeing and Airbus have checks in the autopilot to make sure it doesn't suddenly decide a dive is a perfectly acceptable and safe maneuver. Or perhaps the computer crashes, and the pilots in the newer fly-by-wire aircraft can no longer actually fly the plane. Of course, there are various safety procedures and redundancies built into these systems to prevent a crash (of both the software and the aircraft). However, on the other hand, it's quite obvious that software isn't perfect—both open source and closed source software do crash regularly, and only the simplest "Hello World" program doesn't fail. How can the engineers who design the software systems in the aeronautic, medical, and other life-or-death industries manage to test their software so that it doesn't fail (and if it does fail, at least fail gracefully)? I'm desperately hoping that you're not all going to go: "Oh, I work for Boeing/Airbus/(some other company) and it's not! Have fun on your next flight/hospital visit."

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  • Making simple forms in web applications

    - by levalex
    How do you work with forms in your web applications? I am not talking about RESTful applications, I don't want to build heavy front-end using frameworks like Backbone. For example, I need to add "contact us" form. I need to check data which was filled by user and tell him that his data was sent. Requirements: I want to use AJAX. I want to validate form on back-end side and don't want to duplicate the same code on front-end side. I have my own solution, but it doesn't satisfy me. I make an AJAX request with serialized data on form submit and get response. The next is checking "Content-type" header. html - It means that errors with filling form are exists and response html is form with error labels. - I will replace my form with response html. json and response.error_code == 0 - It means that form was successfully submited. - I will show user notification about success. json and response.error_code != 0 - Something was broken on back-end (like connection with database). other - I display the following message : We have been notified and have started to work with that problem. Please, try it later. The problem of that way is that I can't use it with forms that upload file. What is your practise? What libraries and principles do you use?

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  • What's the best practice to do SOA exception handling?

    - by sun1991
    Here's some interesting debate going on between me and my colleague when coming to handle SOA exceptions: On one side, I support what Juval Lowy said in Programming WCF Services 3rd Edition: As stated at the beginning of this chapter, it is a common illusion that clients care about errors or have anything meaningful to do when they occur. Any attempt to bake such capabilities into the client creates an inordinate degree of coupling between the client and the object, raising serious design questions. How could the client possibly know more about the error than the service, unless it is tightly coupled to it? What if the error originated several layers below the service—should the client be coupled to those lowlevel layers? Should the client try the call again? How often and how frequently? Should the client inform the user of the error? Is there a user? By having all service exceptions be indistinguishable from one another, WCF decouples the client from the service. The less the client knows about what happened on the service side, the more decoupled the interaction will be. On the other side, here's what my colleague suggest: I believe it’s simply incorrect, as it does not align with best practices in building a service oriented architecture and it ignores the general idea that there are problems that users are able to recover from, such as not keying a value correctly. If we considered only systems exceptions, perhaps this idea holds, but systems exceptions are only part of the exception domain. User recoverable exceptions are the other part of the domain and are likely to happen on a regular basis. I believe the correct way to build a service oriented architecture is to map user recoverable situations to checked exceptions, then to marshall each checked exception back to the client as a unique exception that client application programmers are able to handle appropriately. Marshall all runtime exceptions back to the client as a system exception, along with the stack trace so that it is easy to troubleshoot the root cause. I'd like to know what you think about this? Thank you.

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