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  • La bêta 1 de Mandriva Linux 2010.1 est disponible, une évolution en douceur

    Mise à jour du 06.04.2010 par Katleen La bêta 1 de Mandriva Linux 2010.1 est disponible, une évolution en douceur Mandriva vient de publier la bêta 1 de la version 2010.1 de sa distribution Linux. Au menu, pas mal de changements pour une évolution en douceur. Notamment l'arrivée de GNOME 2.30 pour l'environnement de bureau. L'affichage sera partagé dans Nautilus, le client de messagerie instantannée Empathy est revu et corrigé, etc. Cette bêta 1 embarquera un KDE 4.4.2. Il s'agit là d'une version mineure auxquelles ont été ajoutées quelques améliorations. Les nouveautés techniques comprendront un Kernel 2.6.33.1, un Pilote Nouveau pour les cartes NVIDIA et...

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  • Global variable in a Linux shared library

    - by user3730495
    Suppose we have the following setup under Linux, .so library named "libcnt.so" and 3 user space apps: "app1", "app2", "app3". This library does 1 simple thing, it says to the app (app dynamically links the library at runtime) by how many apps it is already linked. Apps should have access to link counter. My knowledge in C and Linux is somewhat limited in this aspect, but as I understand this information should be stored in a global variable inside the shared object. Something like: in libcnt.h extern int cnt_loads; in libcnt.c int cnt_loads = 0; // where each linking increments this counter or something... So, my question is how it should be declared and/or defined inside .so library to guaranty that multiple apps from user space get the same instance of that variable counter?

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  • update-grub is setting a wrong linux root partition

    - by adrian m
    Initially, Ubuntu was installed on another partition (sda5 or sda4). At some point I did manually move the root partition to sda2. Now, the problem is that whenever a new kernel is installed, the automatic regeneration of the menu.lst is using the OLD Linux partition. So I have to manually change in menu.lst the lines : root (hd0,5) into root (hd0,1) How can I configure update-grub to automatically generate menu.lst with the current Linux root partition? I assume that the (hd0,5) was written somewhere at installation, but I couldn't find it.

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  • How do I determine the linux server software/version and email server software/version running

    - by rwilkins
    I just inherited this a single linux box running pop/smtp for a small office (25 users). I'm new to Linux. I think the box is running Debian GNU/Linux 5.0 as the server (this is bannered accross the screen occassionally) but not sure of the release/kernal/build etc. I need to be certain of both the server os and email linux versions in order to perform research, admin and support. Any help/pointers on how to do this is much appreciated.

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  • Music Players in Ubuntu/Linux [closed]

    - by v2r
    Music Player, just like Web Browsers are an important part of today's application repertoire, and not only for entertainment reason. Having tried a few Linux Player over the past years i come to wonder, which Players you prefer and what kind of Players are out there, that you suggest are worth looking into and why!! I used Rhythmbox for a long time, but "Jamendo and Magnatune" plugin are both no longer available in 11.10 and also my covers are not shown, since i stream my music folder from a second partition. aTunes is another great Player, but there are also some flaws which i contacted the developers about. It would be nice if you post some alternatives! --Thank you. Example: Name of Player: aTunes | Homepage Additional Info : aTunes is a java-based Music-Player for Linux/Unix/Windows and ... Only one player-example per answer, please!!

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  • Regular Expression Newbie

    - by Registered User
    I need to parse strings inputs where the columns are separated by columns and any field that contains a comma in the data is wrapped in quotes (commas separated, quoted text identifiers). For this project I need to remove the quotes and any commas that occur between pairs of quotes. Basically, I need to remove commas and quotes that are contained in fields while preserving the commas that are used to separate the fields. Here's a little code I put together that handles the simple scenario: // Sample input 1: This works and covers 99% of the records that I need to parse. string str1 = "[email protected],2010/03/27 12:2:02,,some_first_name,some_last_name,,\"This Address Works, Suite 200\",Some City,TN,09876-5432,9795551212x123,XYZ"; str1 = Regex.Replace(str1, "\"([^\"^,]*),([^\"^,]*)\"", "$1$2"); Console.WriteLine(str1); // Outputs: [email protected],2010/03/27 12:2:02,,some_first_name,some_last_name,,This Address Works Suite 200,Some City,TN,09876-5432,9795551212x123,XYZ Although this code works for most of my records, it doesn't work when a field contains more than one commas. What I would like to do is modify the code so that it remove each instance of a comma contained within the column no matter how many commas there are in the field. I don't want to hard code only handling 2 commas, or 3 commas, or 25 commas. The code should just remove all the commas in the field. Below is an example of what my code doesn't handle properly. // Sample input 2: This doesn't work since there is more than 1 comma between the quotes. string str2 = "[email protected],2010/03/27 12:2:02,,some_first_name,some_last_name,,\"i,l,k,e, c,o,m,m,a,s, i,n ,m,y, f,i,e,l,d\",Some City,TN,09876-5432,9795551212x123,XYZ"; str2 = Regex.Replace(str2, "\"([^\"^,]*),([^\"^,]*)\"", "$1$2"); Console.WriteLine(str2); // Desired output: [email protected],2010/03/27 12:2:02,,some_first_name,some_last_name,,i like commas in my field,Some City,TN,09876-5432,9795551212x123,XYZ Any help would be appreciated for this Regular Expression newbie.

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  • BasicDBObject or QueryBuilder and some newbie questions of Java and mongo

    - by Kevin Xu
    hi I'm a fresh newbie to mongodb Q1 using query=new BasicDBObject(); query.put("i", new BasicDBObject("$gt",13)); and query=new QueryBuilder().put("i").Greaterthan(13).get() is there any difference inside of the system? Q2 I've created a class class findkv extends BasicDBObject{ //is gt gte lt lte public findkv(String fieldname,String op,Object tvalue) { if (op=="") this.put(fieldname,tvalue); else this.put(fieldname, new BasicDBObject(op,tvalue)); } } shall I use it or shall I just use original function? Q3 I've used mongo shell for a few weeks, and was customed to it, and find writing in mongo shell faster and shorter, which side has more advantage, writing in mongo or in java? I shall dump them from mongo to mysql Q4 I've an if (statement==true) return else dowhat; seems can't be compiled I know I can write if (statement!=true) dowhat else return, but can I still write in first style? q5 my eclipse is Eclipse Java EE IDE for Web Developers. Version: Juno Release Build id: 20120614-1722 I'd like to install Perl which I haven't learned yet I choose Install Update http://e-p-i-c.sf.net/updates/testing but it doesn't work, any method to install perl to eclipse manually?

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  • Stupid newbie c++ two-dimensional array problem.

    - by paulson scott
    I've no idea if this is too newbie or generic for stackoverlflow. Apologies if that's the case, I don't intend to waste time. I've just started working through C++ Primer Plus and I've hit a little stump. This is probably super laughable but: for (int year = 0; year < YEARS; year++) { cout << "Year " << year + 1 << ":"; for (int month = 0; month < MONTHS; month++) { absoluteTotal = (yearlyTotal[year][year] += sales[year][month]); } cout << yearlyTotal[year][year] << endl; } cout << "The total number of books sold over a period of " << YEARS << " years is: " << absoluteTotal << endl; I wish to display the total of all 3 years. The rest of the code works fine: input is fine, individual yearly output is fine but I just can't get 3 years added together for one final total. I did have the total working at one point but I didn't have the individual totals working. I messed with it and reversed the situation. I've been messing with it for God knows how long. Any idea guys? Sorry if this isn't the place!

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  • Android newbie installing Eclipse, having issues....

    - by Jeff
    I am a web developer, new to app development and Java/Android. I am about to follow some tutorials to get started learning but I'm running into a wall. The Android dev site says the recommended way to build Android apps is in Java using the Eclipse plug in. So I downloaded Eclipse Classic and unzipped it on to get this error: "A Java Runtime Environment (JRE) or Java Development Kit (JDK) must be available in order to run Eclipse. No Java virtual machine was found after searching the following locations: /Users//Desktop/eclipse/Eclipse.app/Contents/MacOS/jre/bin/java java in your current PATH" Any idea what the issue is and how I can fix it? Again, newbie to java, jre, android, so I apologize if this question has already been asked. In my research I've discovered that most of the posts or solutions I've found are tough for me to follow. There's always a few unclear items that are probably prohibiting me from getting the answer I need. So I'm hoping someone can walk me through installing or configuring whatever I need to regarding Java so I can continue installing Eclipse and begin learning. I should probably note that I'm on Mac OSX 10.6.6 Snow Leopard. Please let me know if you need any other info. Thanks so much in advance for any and all help!!!

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  • Newbie - eclipse workflow (PHP development)

    - by engil
    Hi all - this is a bit of a newbie question but hoping I can get some guidance. I've been playing around with Eclipse for a couple months yet I'm still not completely comfortable with my setup and it seems like every time I install it to a new system I end up with different results. What I'm hoping to achieve is (I think) fairly standard. In my environment I'd like SVN (currently using Subclipse), FTP support (currently using Aptana plugin), debugging (going to use XDebug) and all the usual bells and whistles of development (code completion, refactoring, etc.) My biggest current issue is how to set up my environment to support both a 'development' and 'production' server. Optimally I would be able to work directly against the dev server (Eclipse on my Vista desktop against the VM Ubuntu dev server) and then push to production server (shared hosting). I'd prefer to work directly against the dev server (with no local project files, just using the Connections provided by Aptana) but I'm guessing this won't allow for code-completoin or all the other bells and whistles provided for development. Any thoughts? Kind of an open ended question, but maybe this could be an opportunity for some of you with a great deal of experience using Eclipse to describe your setups so people like me can get some insight into good ways to get set up.

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  • Error in applying patch in Apache

    - by newbie.my
    Recently i have installing apache 2.2.21 from the source for testing purpose. After doing clean installation of apache i want to patch it with the patches provided here: http://www.apache.org/dist/httpd/patches/ Anyway when i put the patch command as mention in the page it show this result: File to patch: CVE-2011-3368.patch 1 out of 1 hunk FAILED -- saving rejects to file CVE-2011-3368.patch.rej Is there something wrong with my patch?If not,how could i verified that the patch has been implemented or not?

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  • Proxying from nginx to Jetty

    - by newbie
    I'm proxying request from nginx to Jetty, but I have problem with request that Jetty receives. Jetty requests shows that request IP address is 127.0.0.1. But I want real server IP and my site has multiple domains, so when request is coming from some domain name to my server, it must available in Jetty request too. nginx config: server { listen 80; ## listen for ipv4 listen [::]:80 default ipv6only=on; ## listen for ipv6 server_name localhost; access_log /var/log/nginx/localhost.access.log; location / { proxy_pass http://127.0.0.1:8080; proxy_set_header X-Real-IP $remote_addr; } } Servlet request: Dump Servlet getMethod: GET getContentLength: -1 getContentType: null getRequestURI: /dump/info getRequestURL: http://127.0.0.1:8080/dump/info getContextPath: getServletPath: /dump getPathInfo: /info getPathTranslated: /tmp/jetty-0.0.0.0-8080-test.war-_-any-/webapp/info getQueryString: null getProtocol: HTTP/1.0 getScheme: http getServerName: 127.0.0.1 getServerPort: 8080 getLocalName: 127.0.0.1 getLocalAddr: 127.0.0.1 getLocalPort: 8080 getRemoteUser: null getUserPrincipal: null getRemoteAddr: 127.0.0.1 getRemoteHost: 127.0.0.1 getRemotePort: 50905 getRequestedSessionId: 6ubs42zhm5q61k5hm84ni3ib isSecure(): false isUserInRole(admin): false getLocale: en_US getLocales: en_US getLocales: en

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  • How to record desktop session with sound on Moblin?

    - by Moblin Newbie
    I have tried to record my desktop session with sound on a netbook running Moblin, but I can't seem to be able to record sound. xvidcap just says error accessing /dev/dsp. Are there some options I should pass to xvidcap? Should I use some other recording application? Update: I am using the latest xvidcap (1.1.7) and have read the FAQ. Unfortunately Moblin' gnome-volume-control looks nothing like what is linked to from the xvidcap FAQ; there is no way to to set or even look at the details the screenshot shows, as far as I know. alsamixer shows pulseaudio is used, if that gives anyone any clues. The device is Acer Aspire One.

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  • Ubuntu 12.04 patched b43 driver compilation error

    - by Zed
    I tried this How do I install this patched b43 driver? guide to install patched b43 driver on Ubuntu 12.04 with 3.2.0-31-generic kernel but I can't pass compilation phase.Here is what I did: wget http://www.orbit-lab.org/kernel/compat-wireless-3-stable/v3.1/compat-wireless-3.1.1-1.tar.bz2 cd compat-wireless-3.1.1-1/ scripts/driver-select b43 make make -C /lib/modules/3.2.0-31-generic/build M=/home/marco/compat-wireless-3.1.1-1 modules make[1]: Entering directory `/usr/src/linux-headers-3.2.0-31-generic' CC [M] /home/marco/compat-wireless-3.1.1-1/compat/main.o In file included from /home/marco/compat-wireless-3.1.1-1/include/linux/compat-2.6.29.h:5:0, from /home/marco/compat-wireless-3.1.1-1/include/linux/compat-2.6.h:24, from <command-line>:0: include/linux/netdevice.h:1153:5: warning: "IS_ENABLED" is not defined [-Wundef] include/linux/netdevice.h:1153:15: error: missing binary operator before token "(" include/linux/netdevice.h: In function ‘netdev_uses_dsa_tags’: include/linux/netdevice.h:1421:9: error: ‘struct net_device’ has no member named ‘dsa_ptr’ include/linux/netdevice.h:1422:31: error: ‘struct net_device’ has no member named ‘dsa_ptr’ include/linux/netdevice.h: In function ‘netdev_uses_trailer_tags’: include/linux/netdevice.h:1431:9: error: ‘struct net_device’ has no member named ‘dsa_ptr’ include/linux/netdevice.h:1432:35: error: ‘struct net_device’ has no member named ‘dsa_ptr’ make[3]: *** [/home/marco/compat-wireless-3.1.1-1/compat/main.o] Error 1 make[2]: *** [/home/marco/compat-wireless-3.1.1-1/compat] Error 2 make[1]: *** [_module_/home/marco/compat-wireless-3.1.1-1] Error 2 make[1]: Leaving directory `/usr/src/linux-headers-3.2.0-31-generic' make: *** [modules] Error 2 To fix that error I added #include <linux/kconfig.h> to /usr/src/linux-headers-3.2.0-31-generic/include/linux/netdevice.h but now I'm getting something else make make -C /lib/modules/3.2.0-31-generic/build M=/home/marco/compat-wireless-3.1.1-1 modules make[1]: Entering directory `/usr/src/linux-headers-3.2.0-31-generic' CC [M] /home/marco/compat-wireless-3.1.1-1/compat/main.o LD [M] /home/marco/compat-wireless-3.1.1-1/compat/compat.o CC [M] /home/marco/compat-wireless-3.1.1-1/drivers/bcma/main.o In file included from /home/marco/compat-wireless-3.1.1-1/include/linux/bcma/bcma.h:9:0, from /home/marco/compat-wireless-3.1.1-1/drivers/bcma/bcma_private.h:8, from /home/marco/compat-wireless-3.1.1-1/drivers/bcma/main.c:8: /home/marco/compat-wireless-3.1.1-1/include/linux/ssb/ssb.h: In function ‘ssb_driver_register’: /home/marco/compat-wireless-3.1.1-1/include/linux/ssb/ssb.h:236:36: error: ‘THIS_MODULE’ undeclared (first use in this function) /home/marco/compat-wireless-3.1.1-1/include/linux/ssb/ssb.h:236:36: note: each undeclared identifier is reported only once for each function it appears in In file included from /home/marco/compat-wireless-3.1.1-1/drivers/bcma/bcma_private.h:8:0, from /home/marco/compat-wireless-3.1.1-1/drivers/bcma/main.c:8: /home/marco/compat-wireless-3.1.1-1/include/linux/bcma/bcma.h: In function ‘bcma_driver_register’: /home/marco/compat-wireless-3.1.1-1/include/linux/bcma/bcma.h:170:37: error: ‘THIS_MODULE’ undeclared (first use in this function) /home/marco/compat-wireless-3.1.1-1/drivers/bcma/main.c: At top level: /home/marco/compat-wireless-3.1.1-1/drivers/bcma/main.c:12:20: error: expected declaration specifiers or ‘...’ before string constant /home/marco/compat-wireless-3.1.1-1/drivers/bcma/main.c:13:16: error: expected declaration specifiers or ‘...’ before string constant /home/marco/compat-wireless-3.1.1-1/drivers/bcma/main.c:182:1: warning: data definition has no type or storage class [enabled by default] /home/marco/compat-wireless-3.1.1-1/drivers/bcma/main.c:182:1: warning: type defaults to ‘int’ in declaration of ‘EXPORT_SYMBOL_GPL’ [-Wimplicit-int] /home/marco/compat-wireless-3.1.1-1/drivers/bcma/main.c:182:1: warning: parameter names (without types) in function declaration [enabled by default] /home/marco/compat-wireless-3.1.1-1/drivers/bcma/main.c:188:1: warning: data definition has no type or storage class [enabled by default] /home/marco/compat-wireless-3.1.1-1/drivers/bcma/main.c:188:1: warning: type defaults to ‘int’ in declaration of ‘EXPORT_SYMBOL_GPL’ [-Wimplicit-int] /home/marco/compat-wireless-3.1.1-1/drivers/bcma/main.c:188:1: warning: parameter names (without types) in function declaration [enabled by default] make[3]: *** [/home/marco/compat-wireless-3.1.1-1/drivers/bcma/main.o] Error 1 make[2]: *** [/home/marco/compat-wireless-3.1.1-1/drivers/bcma] Error 2 make[1]: *** [_module_/home/marco/compat-wireless-3.1.1-1] Error 2 make[1]: Leaving directory `/usr/src/linux-headers-3.2.0-31-generic' make: *** [modules] Error 2 Any suggestion what to try next?

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  • Clone a Hard Drive Using an Ubuntu Live CD

    - by Trevor Bekolay
    Whether you’re setting up multiple computers or doing a full backup, cloning hard drives is a common maintenance task. Don’t bother burning a new boot CD or paying for new software – you can do it easily with your Ubuntu Live CD. Not only can you do this with your Ubuntu Live CD, you can do it right out of the box – no additional software needed! The program we’ll use is called dd, and it’s included with pretty much all Linux distributions. dd is a utility used to do low-level copying – rather than working with files, it works directly on the raw data on a storage device. Note: dd gets a bad rap, because like many other Linux utilities, if misused it can be very destructive. If you’re not sure what you’re doing, you can easily wipe out an entire hard drive, in an unrecoverable way. Of course, the flip side of that is that dd is extremely powerful, and can do very complex tasks with little user effort. If you’re careful, and follow these instructions closely, you can clone your hard drive with one command. We’re going to take a small hard drive that we’ve been using and copy it to a new hard drive, which hasn’t been formatted yet. To make sure that we’re working with the right drives, we’ll open up a terminal (Applications > Accessories > Terminal) and enter in the following command sudo fdisk –l We have two small drives, /dev/sda, which has two partitions, and /dev/sdc, which is completely unformatted. We want to copy the data from /dev/sda to /dev/sdc. Note: while you can copy a smaller drive to a larger one, you can’t copy a larger drive to a smaller one with the method described below. Now the fun part: using dd. The invocation we’ll use is: sudo dd if=/dev/sda of=/dev/sdc In this case, we’re telling dd that the input file (“if”) is /dev/sda, and the output file (“of”) is /dev/sdc. If your drives are quite large, this can take some time, but in our case it took just less than a minute. If we do sudo fdisk –l again, we can see that, despite not formatting /dev/sdc at all, it now has the same partitions as /dev/sda.  Additionally, if we mount all of the partitions, we can see that all of the data on /dev/sdc is now the same as on /dev/sda. Note: you may have to restart your computer to be able to mount the newly cloned drive. And that’s it…If you exercise caution and make sure that you’re using the right drives as the input file and output file, dd isn’t anything to be scared of. Unlike other utilities, dd copies absolutely everything from one drive to another – that means that you can even recover files deleted from the original drive in the clone! Similar Articles Productive Geek Tips Reset Your Ubuntu Password Easily from the Live CDHow to Browse Without a Trace with an Ubuntu Live CDRecover Deleted Files on an NTFS Hard Drive from a Ubuntu Live CDCreate a Bootable Ubuntu 9.10 USB Flash DriveWipe, Delete, and Securely Destroy Your Hard Drive’s Data the Easy Way TouchFreeze Alternative in AutoHotkey The Icy Undertow Desktop Windows Home Server – Backup to LAN The Clear & Clean Desktop Use This Bookmarklet to Easily Get Albums Use AutoHotkey to Assign a Hotkey to a Specific Window Latest Software Reviews Tinyhacker Random Tips Xobni Plus for Outlook All My Movies 5.9 CloudBerry Online Backup 1.5 for Windows Home Server Snagit 10 Windows Media Player Glass Icons (icons we like) How to Forecast Weather, without Gadgets Outlook Tools, one stop tweaking for any Outlook version Zoofs, find the most popular tweeted YouTube videos Video preview of new Windows Live Essentials 21 Cursor Packs for XP, Vista & 7

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  • Autoconf (newbie) -- building with static library

    - by EB
    I am trying to migrate from manual build to autoconf, which is working very nicely so far. But I have one static library that I can't figure out how to integrate. That library will NOT be located in the usual library locations - the location of the binary (.a file) and header (.h file) will be given as a configure argument. (Notably, even if I move the .a file to /usr/lib or anywhere else I can think of, it still won't work.) Manual compilation is working with these: gcc ... -I/path/to/header/file/directory /full/path/to/the/.a/file/itself (Uh, I actually don't understand why the .a file is referenced directly, not with -L or anything. Yes, I have a half-baked understanding of building C programs.) I can use the configure argument to successfully find the header (.h file) using AC_CHECK_HEADER. Inside the AC_CHECK_HEADER I then add the location to CPFLAGS and the #include of the header file in the actual C code picks it up nicely. Given a configure argument that has been put into $location and the name of the needed files are myprog.h and myprog.a (which are both in the same directory), here is what works so far: AC_CHECK_HEADER([$location/myprog.h], [AC_DEFINE([HAVE_MYPROG_H], [1], [found myprog.h]) CFLAGS="$CFLAGS -I$location"]) Where I run into difficulties is getting the binary (.a file) linked in. No matter what I try, I always get an error about undefined references to the function calls for that library. I'm pretty sure it's a linkage issue, because I can fuss with the C code and make an intentional error in the function calls to that library which produces earlier errors that indicate that the function prototypes have been loaded and used to compile. I tried adding the location that contains the .a file to LDFLAGS and then doing a AC_CHECK_LIB but it is not found. Maybe my syntax is wrong, or maybe I'm missing something more fundamental, which would not be surprising since I'm a newbie and don't really know what I'm doing. Here is what I have tried: AC_CHECK_HEADER([$location/myprog.h], [AC_DEFINE([HAVE_MYPROG_H], [1], [found myprog.h]) CFLAGS="$CFLAGS -I$location"; LDFLAGS="$LDFLAGS -L$location"; AC_CHECK_LIB(myprog)]) No dice. AC_CHECK_LIB is looking for -lmyprog I guess (or libmyprog?) so I'm not sure if that's a problem, so I tried this, too (omit AC_CHECK_LIB and include the .a directly in LDFLAGS), without luck: AC_CHECK_HEADER([$location/myprog.h], [AC_DEFINE([HAVE_MYPROG_H], [1], [found myprog.h]) CFLAGS="$CFLAGS -I$location"; LDFLAGS="$LDFLAGS -L$location/myprog.a"]) To emulate the manual compilation, I tried removing the -L but that doesn't help: AC_CHECK_HEADER([$location/myprog.h], [AC_DEFINE([HAVE_MYPROG_H], [1], [found myprog.h]) CFLAGS="$CFLAGS -I$location"; LDFLAGS="$LDFLAGS $location/myprog.a"]) I tried other combinations and permutations, but I think I might be missing something more fundamental....

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  • Haskell newbie on types

    - by garulfo
    I'm completely new to Haskell (and more generally to functional programming), so forgive me if this is really basic stuff. To get more than a taste, I try to implement in Haskell some algorithmic stuff I'm working on. I have a simple module Interval that implements intervals on the line. It contains the type data Interval t = Interval t t the helper function makeInterval :: (Ord t) => t -> t -> Interval t makeInterval l r | l <= r = Interval l r | otherwise = error "bad interval" and some utility functions about intervals. Here, my interest lies in multidimensional intervals (d-intervals), those objects that are composed of d intervals. I want to separately consider d-intervals that are the union of d disjoint intervals on the line (multiple interval) from those that are the union of d interval on d separate lines (track interval). With distinct algorithmic treatments in mind, I think it would be nice to have two distinct types (even if both are lists of intervals here) such as import qualified Interval as I -- Multilple interval newtype MInterval t = MInterval [I.Interval t] -- Track interval newtype TInterval t = TInterval [I.Interval t] to allow for distinct sanity checks, e.g. makeMInterval :: (Ord t) => [I.Interval t] -> MInterval t makeMInterval is = if foldr (&&) True [I.precedes i i' | (i, i') <- zip is (tail is)] then (MInterval is) else error "bad multiple interval" makeTInterval :: (Ord t) => [I.Interval t] -> TInterval t makeTInterval = TInterval I now get to the point, at last! But some functions are naturally concerned with both multiple intervals and track intervals. For example, a function order would return the number of intervals in a multiple interval or a track interval. What can I do? Adding -- Dimensional interval data DInterval t = MIntervalStuff (MInterval t) | TIntervalStuff (TInterval t) does not help much, since, if I understand well (correct me if I'm wrong), I would have to write order :: DInterval t -> Int order (MIntervalStuff (MInterval is)) = length is order (TIntervalStuff (TInterval is)) = length is and call order as order (MIntervalStuff is) or order (TIntervalStuff is) when is is a MInterval or a TInterval. Not that great, it looks odd. Neither I want to duplicate the function (I have many functions that are concerned with both multiple and track intevals, and some other d-interval definitions such as equal length multiple and track intervals). I'm left with the feeling that I'm completely wrong and have missed some important point about types in Haskell (and/or can't forget enough here about OO programming). So, quite a newbie question, what would be the best way in Haskell to deal with such a situation? Do I have to forget about introducing MInterval and TInterval and go with one type only? Thanks a lot for your help, Garulfo

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  • PERL newbie : get a proper minimal debug_mode solution

    - by Michael Mao
    Hi all: I am learning PERL in a "head-first" manner. I am absolutely a newbie in this language: I am trying to have a debug_mode switch from CLI which can be used to control how my script works, by switching certain subroutines "on and off". And below is what I've got so far: #!/usr/bin/perl -s -w # purpose : make subroutine execution optional, # which is depending on a CLI switch flag use strict; use warnings; use constant DEBUG_VERBOSE => "v"; use constant DEBUG_SUPPRESS_ERROR_MSGS => "s"; use constant DEBUG_IGNORE_VALIDATION => "i"; use constant DEBUG_SETPPING_COMPUTATION => "c"; our ($debug_mode); mainMethod(); sub mainMethod # () { if(!$debug_mode) { print "debug_mode is OFF\n"; } elsif($debug_mode) { print "debug_mode is ON\n"; } else { print "OMG!\n"; exit -1; } checkArgv(); printErrorMsg("Error_Code_123", "Parsing Error at..."); verbose(); } sub checkArgv #() { print ("Number of ARGV : ".(1 + $#ARGV)."\n"); } sub printErrorMsg # ($error_code, $error_msg, ..) { if(defined($debug_mode) && !($debug_mode =~ DEBUG_SUPPRESS_ERROR_MSGS)) { print "You can only see me if -debug_mode is NOT set". " to DEBUG_SUPPRESS_ERROR_MSGS\n"; die("terminated prematurely...\n") and exit -1; } } sub verbose # () { if(defined($debug_mode) && ($debug_mode =~ DEBUG_VERBOSE)) { print "Blah blah blah...\n"; } } So far as I can tell, at least it works...: the -debug_mode switch doesn't interfere with normal ARGV the following commandlines work: ./optional.pl ./optional.pl -debug_mode ./optional.pl -debug_mode=v ./optional.pl -debug_mode=s However, I am puzzled when multiple debug_modes are "mixed", such as: ./optional.pl -debug_mode=sv ./optional.pl -debug_mode=vs I don't understand why the above lines of code "magically works". I see both of the "DEBUG_VERBOS" and "DEBUG_SUPPRESS_ERROR_MSGS" apply to the script, which is fine in this case. However, if there are some "conflicting" debug modes, I am not sure how to set the "precedence of debue_modes"? Also, I am not certain if my approach is good enough to Perlists and I hope I am getting my feet in the right direction. One biggest problem is that I now put if statements inside most of my subroutines for controlling their behavior under different modes. Is this okay? Is there a more elegant way? I know there must be a debug module from CPAN or elsewhere, but I wanna a real minimal solution that doesn't depend on any other module than the "default" And I cannot have any control on the environment where this script will be executed... Many thanks to the suggestions in advance.

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