January 2004 - openSUSE Programming - openSUSE Mailing Lists

WAS "A good book on C programming", now an APPOLOGY
by Gavin Henry 04 Mar '04

04 Mar '04

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Dear Everyone, I was had this pointed out to me, by Simon Perreault <nomis80(a)nomis80.org> (with my reply): "On Saturday 27 Dec 2003 8:49 pm, you wrote: > 1) Please do not cross-post. (This means sending the same message to many > lists.) OK, guilty, but I wanted a varied response, as different people subscribe to different lists. > > 2) Please stay on topic. This has nothing to do with Fedora. Fedora is GNU/Linux, there are C programmers, like you that use Fedora, and it is a general discussion list. What's the problem? I'm not asking for money for for you to join some crazy scheme. This kind of attitude annoys me about GNU/Linux, I am not wasting anyones time, so I don't see what the problem is." And his last reply: "On December 27, 2003 16:11, you wrote: > This kind of attitude annoys me about GNU/Linux, I am not wasting anyones > time, so I don't see what the problem is. Yes, you are wasting time (and bandwidth, as there are some people on very slow connections) when you are not on topic. This list is not even about GNU/Linux, it is about Fedora. General Linux questions do not belong here. This is Fedora-related stuff only. There are tons of Linux and C mailing lists. This is a quick lesson (that everyone must learn, I did too) on netiquette. You should Google a bit on that topic, particularly on stuff related to mailing lists." I am sorry if I have wasted everyones time and bandwidth, but I have spent the last 3 days searching for up to date links and book reviews, some things you never find, like the website: http://www.accu.org/bookreviews/public/ recommended by another user. I admit, I have cross posted, as I not only use Fedora, but Debian, SUSE and Gentoo. These are all different distro's with different user bases. I wanted to get a good feel of what are good texts from all the C programmers out their. I didn't get a response like above from anyone else. Even Alan Cox replied to me. What I don't understand is, and I quote, "This list is not even about GNU/Linux, it is about Fedora." What is Fedora then? Again, sorry to waste everyones time, but you have all helped me out. - -- Regards http://www.magicfx.co.uk http://www.suretecsystems.com -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.3 (GNU/Linux) iD8DBQE/7f0YgNqd7Kng8UoRAimuAKCikZFb2yBGtrHss8AWHmb7pPwQMwCg4OAT hiT3sr0rPLJBLtQl/uiqQOU= =mTvq -----END PGP SIGNATURE-----

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A hidden race condition in basic pthread program?
by praisetazio 30 Jan '04

30 Jan '04

The following code should simulate a port with M places and N ships accessing to it. The problem: in the "entering_request" function, the program controls how many ships are in port, if there are too many ships the program should block on a condition variable. The problem is that it does not work, and I usually get more than M ships at runtime. I think that I am misunderstanding something, anybody could enlighten me? #include <pthread.h> #include <stdio.h> #include <stdlib.h> #include <time.h> #define N 10 #define M 5 struct port { pthread_mutex_t mutex; pthread_cond_t full; int ships; int waiting; } Port = { PTHREAD_MUTEX_INITIALIZER, PTHREAD_COND_INITIALIZER, 0, 0 }; void* ship (void* arg); int main() { void* nothing; pthread_t ships[N]; int i; pthread_setconcurrency(N); for (i=0; i<N; i++) pthread_create (&ships[i], NULL, ship, NULL); for (i=0; i<N; i++) pthread_join (ships[i], &nothing); printf("The end\n"); return 0; } void entering_request() { pthread_mutex_lock(&Port.mutex); if (Port.ships>=M) { Port.waiting++; printf("ship %d blocked\n", pthread_self()); pthread_cond_wait(&Port.full, &Port.mutex); printf("ship %d unblocked\n", pthread_self()); Port.waiting--; } } void entering() { printf ("ship %d enters the port", pthread_self()); printf ("\n%d ships in port\n", Port.ships); } void leaving_entrance() { Port.ships++; printf("Ships inside the port: %d\n", Port.ships); pthread_mutex_unlock(&Port.mutex); } void stationing () { int l, i; srand(time(NULL)); printf("La ship %d is inside with other %d ships.\n", pthread_self(), Port.ships); l = rand(); /* Wasting time */ for (i=0; i<l; i++); } void exit_request() { pthread_mutex_lock(&Port.mutex); } void exiting() { printf ("ship %d out of the port\n", pthread_self()); printf ("%d ships\n remain in port", Port.ships); } void leaving_exit() { Port.ships--; if (Port.waiting) pthread_cond_signal (&Port.full); pthread_mutex_unlock(&Port.mutex); } void* ship (void* arg) { int i; for (i=0; i<3000; i++) { entering_request(); entering(); leaving_entrance(); stationing(); exit_request(); exiting(); leaving_exit(); } return NULL; }

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Thread sleep
by Lukacs Zsolt 27 Jan '04

27 Jan '04

Hi, I have created a process which cretes some threads. I would like to sleep one thread (let's say for 500 ms) while the other threads are still working. Does anybody know how to do that? I have already tried to use the sleep() function but it seems that it the whole process goes to sleep not just olny one of the threads owned by the process. Thanks Zsolt

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relocation error: undefined symbol glDeleteProgramARB
by Indra Geys 25 Jan '04

25 Jan '04

Hello, I am just changed from redhat 9.0 to suse and I have some problems with my code. I managed to solve some compile errors already but if I now start up my program, then I get some error: relocation error: undefined symbol: glDeleteProgramARB and it crashes. This glDeleteProgramARB is certainly in defined in the header gtkglext and it is also in the lib which is in my path (compilation and linking gives no problem) Does somebody knows what causes this problem, and more important: how can I solve it? Thanks, Indra

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Supercomputers and Linux s/w
by Maura Edelweiss Monville 25 Jan '04

25 Jan '04

I'm runnig many simulations with one only different paramater value. The reason is to generate statistical data. I have an account on the super-computer center shown in the following web page: http://harpo.wustl.edu/hardware.html There seems to be a Linux system (SGI Altix) but because of the way my account was set up my entry is on Harpo which runs Irix. I'll be runnin on batch so I do not know if this is important at all. I'd like to be able to recompile and run my simulation (developed on SuSE) with the least possible discomfort from s/w environment incompatibilities ... There is no GNU Scientific Library which I need. My question for you is: What should I ask this center administrator for ? They are amenable to install some s/w upon user request ... In the case GSL cannot run/be installed then is ther any replacement for a good Random Number Generator that you'd advice ? I like SuSE and am very gratefull to all generous people that have been helping me regularly. The only drawback is when it comes to porting my project to some other platform ... Thank you in advance for your help. maura Thank you for clarifying my ideas. Maura

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Suse and LVM VFS-lock patch
by Rajesh Saxena 20 Jan '04

20 Jan '04

Greetings list............ after posting to the linux-lvm mailing list I am informed that there is a patch[1] for LVM which allows more reliable filesystem snapshots. The last patch for the 2.4 kernel [2] seems to be for 2.4.20 but Suse running 2.4.21 instead. Question to Suse developers or experienced kernel programmer: Do the default kernel have this patch included? [1] http://marc.theaimsgroup.com/?l=linux-lvm&m=107426158117112&w=2 [2] http://tech.sistina.com/cgi-bin/viewcvs.cgi/LVM/PATCHES/ ______________________________________________________________________ Post your free ad now! http://personals.yahoo.ca

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libpthread.so.0 not found trying to link simple app. Library is present in /lib
by Burt Bicksler 19 Jan '04

19 Jan '04

Hi, I’m trying to build a simple hello world test application using pthreads. This is on a stock SUSE Pro 8.2 installation with all of the latest patches installed. During the link the linker whines that it cannot find libpthread.so.0. I have tried presenting this as -l/lib/libpthread.so.0 (which is where the lib physically resides). This doesn’t change the problem, still no joy with linking the application. I’m probably doing something wrong, but I’ve scanned the web with Google and, while I’ve found similar problems with other libraries mentioned all of those appear to be related to not having the library installed. I haven’t been able to track down a good specific example showing what library to link with, so I’m making the assumption that libpthread.so.0 is the correct one, but it doesn’t appear to be recognized by the linker. Has anyone else encountered this problem, and if so what was the solution? If you can point me to a specific document that details the settings to use to build a “hello world” threaded application on SUSE 8.2 that would be great. Thanks, Burt --- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com) Version: 6.0.558 / Virus Database: 350 - Release Date: 1/2/2004

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newer Kdevelop and dependencies on KDE 3.2
by Ivan Sergio Borgonovo 19 Jan '04

19 Jan '04

Anyone made Kdevelop 3 packages for 9.0 without making them dependent on KDElibs for KDE 3.2? I'm trying to make the package right now but compiling it is pretty long even on an Athlon 2500+ 1Gb RAM. Correcting mistakes in the spec file is pretty expensive.

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glade prob
by oguz eren 19 Jan '04

19 Jan '04

Hi, I'm trying to learn glade. autogen.sh failed on my first try; giving the error below: ./configure: line 4068: syntax error near unexpected token `PACKAGE,' ./configure: line 4068: `PKG_CHECK_MODULES(PACKAGE, $pkg_modules)' Then i learned that i had to install pkgconfig; i did so; but this time autogen gave the following error: checking for gtk+-2.0 >= 2.0.0... Package gtk+-2.0 was not found in the pkg-config search path. Perhaps you should add the directory containing `gtk+-2.0.pc' to the PKG_CONFIG_PATH environment variable No package 'gtk+-2.0' found configure: error: Library requirements (gtk+-2.0 >= 2.0.0) not met; consider adjusting the PKG_CONFIG_PATH environment variable if your libraries are in a nonstandard prefix so pkg-config can find them. How do i have to set PKG_CONFIG_PATH environment variable? Thanks in advance.

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RE: [suse-programming-e] Set uid on executables
by Hallingstad Håkon 19 Jan '04

19 Jan '04

Try to write /usr/bin/passwd without setuid/setgid. I thought the hole point with the shebang-scheme was that we could write scripts so that they would seem to work excatly as compiled programs. The kernel does not make the system more safe by ignoring setuid/setgid on scripts, since I can always write a setuid/setgid wrapper C program that calls my script. The kernel should instead provide a simple API, that setuid/setgid on programfiles works in the same manner no matter how the program is implemented. But anyway, I got the answer I was looking for. Case closed. -----Original Message----- From: Derek Fountain [mailto:derekfountain@yahoo.co.uk] Sent: 19. januar 2004 10:31 To: suse-programming-e(a)suse.com Subject: Re: [suse-programming-e] Set uid on executables > Why do not pids.sh also report euid=0? Does this mean setuid/setgid on > bash scripts are useless and misleading? Basically, yes. A better way of looking at it is that setuid scripts are a security nightmare - the shell is so easy to corrupt that it's very hard to make a setuid script safe. For this reason the kernel doesn't allow them. This is a good thing - honest! -- > eatapple core dump -- To unsubscribe, email: suse-programming-e-unsubscribe(a)suse.com For additional commands, email: suse-programming-e-help(a)suse.com Archives can be found at: http://lists.suse.com/archive/suse-programming-e

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