LINUX programming Forum RSS Feed

Making a keyboard in Linux

Fri, 03 Jul 2009 04:43:33 -0700

Hi,

I am trying to make a keyboard application in C on Linux.
Please help with the source code. it wud be a keyboard used in Electronic Cash Registers.

Reply soon

Low level program to read mjpeg stream

Fri, 26 Jun 2009 02:47:13 -0700

Hi all
Well first I’ll just say I am a complete Linux beginner, but I have done vbs, js, php, html web type stuff so I’m not a complete beginner to programming.

However I've been trying to learn C and python but it’s not making a huge amount of sense.

I am wanting to make a simple low level program that copies an image from a mjpeg stream on 192.168.0.1/videostream.cgi for example to a variable then save that variable to a file on my system.

I am aware that there are programs out there that would do this but I still want to make my own.

Any help?
Thanks Rufe0

Low level program to read mjpeg stream

Fri, 26 Jun 2009 02:46:01 -0700

Running Three Shells with a Shell

Thu, 18 Jun 2009 13:59:12 -0700

Okay, so I had these three bat files I converted to shells so I could run this on Linux, which I'm operating through PuTTy.

I made another shell file which would run the other three: 1.sh, 2.sh, and 3.sh, with a five second pause between each. It looks like this:

./1.sh
sleep 5
./2.sh
sleep 5
./3.sh

My problem is that 2.sh is supposed to connect to 1.sh, but the shell won't continue to run 2.sh until 1.sh is responding. I hope you understand what I'm saying here. Any help appreciated.

NCurses Help

Sun, 31 May 2009 00:34:05 -0700

Hi,

I have create an application using ncurses. This program is run from a boot disk and it is called immediately once the system boots from the boot disk. After the GUI is displayed using ncurses, the system is still loading some of the drivers or etc that print messages on the screen which overwrite my GUI. Is there a way to prevent the messages from overwriting my GUI?

Is there some function which I can call to refresh the screen during intervals automatically?
If it has to be done manually, I think I will need to call a separate thread to start a timer because once the GUI loads, I will call getch() to wait for user input.

Thanks.

how can I get the development document in linux

Tue, 26 May 2009 15:26:52 -0700

hello everyone,i am a coder on win.i want to develop software onder linux.but,there isn't good document on linux.
i've search lots of data,but most of them is teaching me how the kernel is working.
but i only attention that what API can i use to build my program onder linux.

can you suggest some books?

while(1)
{
thanks();
}

Linux Version number and hardwares list

Mon, 25 May 2009 00:30:54 -0700

Hi,

I am looking for a C/C++ code to get the Linux Version number and the hardwares list in the system like drive size, RAM size etc.

Also, Is is possible to get the OS version and hardwares list using same code on any linux flavour?? For e.g. Fedora, ubuntu, Debian etc?

Can anyone suggest some code for this.

Any help is greatly appreciated.

Thanks
Arun

atomic operations in application code

Wed, 20 May 2009 16:16:06 -0700

hi all,

this is my first post here.

i need an atomic counter in a linux app, the same as InterlockedIncrement etc in windows.

i've found a number of solutions on the web, all explained with skeletal brevity, all involving inline assembler or dubious includes of non-installed kernel headers..

does anybody know of a good discussion/turorial on this subject, or of a canonical and robust solution. i can't believe it is still being solved ad hoc, as it is a basic requirement for some tasks.

cheers

How to auto keystroke with Xlib?

Wed, 06 May 2009 02:48:56 -0700

Hey,i am very very freshman with X window programming.
In order to free my hand when I read ebooks I need one simple programe to automaticly press down arrow.

The idea is simple I hope it looks like xkill command no GUI and works for any apllications.

I've been googling for two days but i haven't got any useful information about automatic keystroke with Xlib.

Hope someone here could help me.

Ching

error:CPU you selected does not support x86-64 instruction?

Thu, 23 Apr 2009 21:06:01 -0700

I have a C application in Suse Linux.
when I build it on linux, show this error:

sha1.c:1: error: CPU you selected does not support x86-64 instruction set

I use Suse x86-64bits. but 32-bit application should run on 64-bit architecture.
I do not know my program is 32-bits or 64-bits. but when i use 64-bit architecture, there should not occur any error or problem.

can anyone help me?

thanks.

Virtualization Training

Wed, 15 Apr 2009 05:10:54 -0700

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Thanks and warm regards,
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How to update the content of an XML file using libxml2

Sun, 12 Apr 2009 04:11:31 -0700

Hi,

I am using libxml2 for my application which is written in C. I am able to parse my XML configuration file and read all the values. But now i want to modify some values and store them back in the same file.

Can anybody provide any help. A sample code would be a great help.

thanks,
Gaurav

Semaphore for UDP socket

Thu, 02 Apr 2009 00:29:58 -0700

Hi all,

I'd like to know if it's possible to have the following behaviour with a UDP socket.
1. Have a thread waiting for data to read on the socket.
2. Increase a semaphore each time a new packet arrives.
3. Have another thread waiting on the semaphore and reading one and only one packet for each count of the semaphore.

The problem with select is that it wakes up as long as data is available for reading, and not only when a new packet arrives.
Can epoll help me in doing that (I can't figure out from the man pages)?

Thanks.

Reading the symbols using LIB BFD

Thu, 26 Mar 2009 13:23:12 -0700

Hi all,
I am new to qnx programming.
I would like to read the symbol information i.e., type, address and value for a given symbol using the libbfd.a
If the symbol is a structure, I would like to read the information of all its members.
I would like to know if anyone has any information or sample code on how to achieve this.

Thanks,
Sushma

insmod:error inserting "fliusb.ko": -1 File exists

Tue, 24 Mar 2009 22:00:02 -0700

hi...
i encounter a prblem while running some driver in linux.it shows

insmod:error inserting "fliusb.ko": -1 File exists

now i know that the file already exists,but it has problem in inserting the file.earlier it worked correctly but now it shows error.
plzzz help me as soon as possible.

How to send webcam stream to another computer.

Tue, 17 Mar 2009 00:30:58 -0700

Hi!
How could I send video stream to another computer on the Internet? I am using C++ language and wish to use openCV ang ffmpeg libraries, but is it possible? I know that I can create jpeg image from video stream and send it in UDP packets, but I dont want to do it because of poor compresion. That's why I wish to send mpeg4 stream. Important is, that I dont need anything like rev, ff and recording. I need only to display video stream and gain no less than 25 fps.
Best Regards!

PS. It should be p2p communication. I want to avoid something like communications servers etc.

Please read

Sat, 14 Mar 2009 08:37:56 -0700

Will someone please read my "Linux Programming" question below and answer me, please. It's a very shot and simple question.

Reading the debug information

Fri, 13 Mar 2009 10:38:59 -0700

Hi all,
I am really new to the linux environment.
I want to be able to monitor all the global variables in my application
running on linux at runtime. There would be another client application
running on another machine which would receive the values of the global
variables over UDP and display them.
I cannot use a debugger as I want to be able to watch the variables change at runtime and also plot them graphically as it changes.
I would like to include symbol/debug information in the executable and parse that from my application.
Are there any libraries that I can use to read the symbol information?
Also, if the variable I am trying to find is a class or a structure, then will I also be able to find the information regarding its members?

Thanks,
Sushma

Linux Programming

Thu, 05 Mar 2009 09:34:46 -0700

So what languages are best for writing programing to run on Linux?

Linux fopen() mistery. Help required.

Tue, 03 Mar 2009 03:27:34 -0700

Hello!

I'm having problems with fopen() call in Linux.

I have shared library (created by myself) that implements some file operations:

int lib_func(char* file_name) {
...
  fd = fopen(file_name, "r");
  if(!fd) {... exit with error ...}
...
  do something useful using fd
...
  fclose(fd);
}

Also I have two programs (pr1 and pr2) that use that library and they call lib_func(): lib_func("/dir/dir/file");

Here is the mystery:
- if I run pr1 from command line, lib_func() is called successfully and file is accessed as required;
- if I run pr2 as daemon, lib_func() is called but fopen() fails with ERRNO=2 (No such file or directory).
How can I fix it to run with pr2?

What I have checked so far:
1. I start pr1 and pr2 strictly in different times (no simultaneous running).
2. File in question exists (I can view it, copy it, delete it from shell).
3. Path to file is absolute.
4. No compile warnings/errors.
5. pr2 is in userspace.
6. Both processes are running from root user and have rights for the file access (777).
7. SELinux is in permissive mode (no effect on system operation).
8. No other process is blocking the file.

Any ideas?

New to Linux

Sun, 01 Mar 2009 22:38:35 -0700

I'M trying to install Limewire on Ubuntu Linux but I'M getting the following error message.

Failed to run gdebi-gtk '--non-interactive' '/home/other/Desktop/LimeWireLinux.deb' as user root.

The underlying authorization mechanism (sudo) does not allow you to run this program. Contact the system administrator.

I am also not able to login into the Terminal using the "su" command to install other programs. I the this error message, even though I'M using the same password I use to login to the screen name.

su: Authentication failure
other@garrett-desktop:~$
other@garrett-desktop

Thanks for any and all help.

Ethernet Loopback

Sun, 01 Mar 2009 11:41:51 -0700

Hi everybody!

Is there a free software availaible to emulate/generate an Ethernet loopback on a desktop/notebook/netbook?

I have searched the net for that kind of software but didn't get any useful results.

The software should be able to make a Layer2 loop by swapping source and destination MAC, while leaving the rest of the frame unchanged.

Another useful thing would be to make a Layer3 loop by swapping MACs and in addition source and destination IP while leaving the rest of the packet as is.

So this software should work like a "reflector" for the addressed Layers.

I'm not sure if this is the right place to ask such a question and the more I'm waiting for your responses.

Cheers

Gerhard

C#

Sat, 21 Feb 2009 09:10:05 -0700

Let me start be explaining just how much of an inexperienced programmer I am. I started TRYING to learn C++ some years back with a dream of being able to write games. But the further est I ever got was simple DOS based screen programs,using the simplest of functions and a few loops and if/els statements. I would read a book till I finally couldn't understand any more, get mad and through it down, and buy another one.

I just bought a two book set for game programming using C#. The books are called "Learn Programming Now! - Microsoft XNA Game Studio 2.0" & "Microsoft Visual C# 2005 Step by Step".

So here are my questions.

First, is there any real hope of me learning to program?

Is C# really a good alternative programming language for C++?

I would eventually like to start writing programs for Linux, is this a good language for that as well? If not, then what is?

Even though I would like to eventually learn to write programs for Linux, I chose these books because I though it would be a good place to start due to the tools available and the suppose ed ease. And because it look similar to C++. So if I learn on a Microsoft based system like XNA, will I still be able to transist to Linux with that programming knowledge?

When I use tools like XNA, I am equiped and taught to program using so many tools and pre-programmed libraries, I fell like I might not really be learning to program at all, any input on that?

Thanks everyone for all your help and replies.

chat program using linux networking

Fri, 13 Feb 2009 14:03:49 -0700

Hi everyone,
I have just started network programming on linux and i wrote some very basic client-server programs. My university has a lan and i thought it would be fun to write a chat program for the lan, but i dont know how to proceed, can anyone help me out?

Thanks

parser project needs perl/C programmer

Wed, 04 Feb 2009 10:46:47 -0700

I'd like to know if anyone of you would be interested in being payed ($$$) to program a BNF like parser.
Intermediate to advanced programmer skills required because the project deals allot with pointers and memory updates and
inter-mixes c/c++/perl code. Anyone interested visit http://www.angelfire.com/cppcode/blog/spec_0.txt for futher details

cvv3@yahoo.com