linux

linux script, standard directory locations.

I am trying to write a bash script to do a task, I have done pretty well so far, and have it working to an extent, but I want to set it up so it's distributable to other people, and will be opening it up as open source, so I want to start doing things the "conventional" way. Unfortunately I'm not all that sure what the conventional way i...

Segmentation Fault?

Hello, when I run this program while inputting a number greater than 46348, I get a segmentation fault. For any values below it, the program works perfectly. I am using CodeBlocks 8.02 on Ubuntu 10.04 64-bit. The code is as follows: int main() { int number = 46348; vector<bool> sieve(number+1,false); vector<int> primes; ...

Grep: Excluding a specific folder using

Say our folder structure looks like this: /app /app/data ... /app/secondary /app/secondary/data I want to recursively search /app/data but I do not want to search /app/secondary/data. From within the app folder, what would my grep command look like? ...

How do you go about setting up monitoring for a non-web frontend process?

I have a worker process that is running in a server with no web frontend. what is the best way to set up monitoring fot it? It recently died for 3 days, and i did not know about it ...

Embedding Ruby, calling a function from C

Hi, I'm writing an app that calls ruby code from c. I am having a little difficulty and wondered if anyone could point me in the rite direction. I currently have in my C. #include ruby.h main() { ruby_init(); rb_require("myRubyFile"); rb_funcall(rb_module_new(), rb_intern("RubyFunction"), 0, NULL); } My ruby file is in the sam...

*-Operator in gas

Hi, can anyone explain what the * in the gnu assembler does? Example: jmp *0x804a004 This is an entry in a procedure linkage table (plt), maybe someone can clarify what this instruction does and what the * stands for. ...

Would it be simply better to use the system's functions rather than use the language?

There are many scenarios where I've questioned PHP's performance with some of its functions, and whether I should build a complex class to handle specific things using its seemingly slow tools. For example, Complex regular expressions with sed and processing with awk would seemingly be exponential in performance rather than making PHP's...

C++ Programming in Linux Platform

I am a software engineer and i work in VC++, C++ in WIndows OS. Are there any major differences when it comes to coding in C++ in Linux environment. Or is it just some adjustments that we have to make when we need to code in C++ in Linux. ...

Why wont this entire word doc file generate from my php script?

Here's the php script I'm using on a linux environment: <?php include("../_inc/odbcw.php"); //connect string $cat = $_GET["cat"]; if($_GET["st"]){$crs_query = "select crs_no, title, credits, abstr, prereq, coreq, lab_fee from xxx where active = 'Y' and cat = '".$cat."' and spec_top = 'Y' and prog='UNDG' order by crs_no";} else {$crs...

Using pipes in Linux with C

Hi, I'm doing a course in Operating Systems and we're supposed to learn how to use pipes to transfer data between processes. We were given this simple piece of code which demonstrates how to use pipes,but I'm having difficulty understanding it. #include <stdio.h> #include <stdlib.h> #include <unistd.h> main() { int pipefd [2],...

C++ Win/Linux thread syncronization Event

Hello I have some code that is cross-platform by unsing #ifdef OS, I have a Queue protected by a CriticalSection on Windows, and by a pthread_mutex_t on Linux. I would like to implement a Wait(timeout) call that would block a thread until something has been enqueued. I though about using WaitForSingleObject on windows but it don't seem...

Client connections with epoll

Hi, I'm programming an application(client/server) in C++ for linux using epoll y pthreads but I don't know how to handle the connect() calls for attach a new connection in the descriptor list if a loop with epoll_wait() is running(Edge-triggered), How to can I do it?... I could to use a dummy file descriptor to trigger an event and scap...

CreateTimerQueue for linux

Anyone know if there is any function similar to CreateTimerQueue on linux? Or do I have to make my own. ...

Reading a SquashFS archive

(SquashFS is a compressed filesystem - http://en.wikipedia.org/wiki/SquashFS) I'm looking for a way to read a SquashFS filesystem from a program. So far, I've know about the in-kernel drivers for it, but I'm sure that a userspace library for it must exist somewhere. Any language would be fine, but C is preferred. Just mounting the fil...

Is it easier to write filesystem drivers in userspace than in kernel space?

I will use the Linux NTFS driver as an example. The Linux kernel NTFS driver only has very limited write support in the kernel, and after 5 years it is still considered experimental. The same development team creates the ntfsmount userspace driver, which has almost perfect write support. Likewise, the NTFS-3G project which is written ...

building Mozilla Spider Monkey on Ubuntu

Hi. I'm trying to build spider monkey on ubuntu 10.04 (lucid). However, when I run autoconf2.13 on the js/src directory, it tells me there is no configure.in file. I can't just do the usual ./configure > make > sudo make install , either. What's up with it? ...

Doubts in System call mechanism in linux

We transit from ring3 to ring0 using 'int' or the new 'syscall/sysenter' instruction. Does that mean that the page tables and other stuffs that needs to be modified for the kernel is automatically done by the 'int' instruction or the interrupt handler for the 'int 0x80' will do the required stuff and jump to the respective system call. ...

Easily measure elapsed time

I am trying to use time() to measure various points of my program. What I don't understand is why the values in the before and after are the same? I understand this is not the best way to profile my program, I just want to see how long something take. printf("**MyProgram::before time= %ld\n", time(NULL)); doSomthing(); doSomthingLo...

sendto on Tru64 is returning ENOBUF

Hi, I am currently running an old system on Tru64 which involves lots of UDP sockets using the sendto() function. The sockets are used in our code to send messages to/from various processes and then eventually on to a thick client app that is connected remotely. Occasionally the socket to the thick client gets stuck, this can cause so...

Scaling a ruby script by launching multiple processes instead of using threads.

I want to increase the throughput of a script which does net I/O (a scraper). Instead of making it multithreaded in ruby (I use the default 1.9.1 interpreter), I want to launch multiple processes. So, is there a system for doing this to where I can track when one finishes to re-launch it again so that I have X number running at any time....