Programming :: Debugging A Simple Server Supporting Multiple Clients

Sep 24, 2009

I don't have any problem when I'm communicating with one client. The problem starts when I connect another client.The server eventually ignores the older clients and responds only to the latest one.The working mechanism is simple: Accept connections and print messages received from multiple clients.

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Programming :: Recommend A Simple Png-supporting Image Library?

May 14, 2011

I want to build a simple OCR program and I was wondering what library to use. The images are saved on my hdd as colour .png files, i won't be using any effects on them but I will be working with pixels a lot, so direct access to them would really be great.So I was curious if there's a lib that provides direct access to individual pixels and pretty much nothing else (libpng, devIL or QImage from qt are all good but each has it's downfalls).

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Programming :: No Debugging Symbols Found (not The Simple Case)?

Jan 6, 2011

I wasn't sure where to put this so if I need to move it just let me know.I have a strange problem that I cannot figure out. When I use gdb to debug our rpm-installed program, it says (no debugging symbols found) when it loads. Thing is, when I use nm on the program it can print the symbols, and even stranger is if I use gdb on the program before it is packed up by rpmbuild it loads the debug symbols just fine.Our program is built via the standard make using:GS=-g -Wall-pedantic and as I mentioned I can debug the resulting program. After the build, I package it up using:

cmd="rpmbuild -v -bb ptsnmp.spec --define "ver ${cmvc_release}" --define "rel ${cmvc_level}" --define "_topdir $rpmdir""When this package is installed via rpm, the binary on the machine shows all the debug info via nm, file shows it is not stripped:pt_snmp: ELF 64-bit LSB executable, AMD x86-64, version 1 (SYSV), for GNU/Linux 2.6.9, dynamically linked (uses shared libs), for GNU/Linux 2.6.9, not strippedyet when I try to debug it I get the no debugging symbols found.This is really taxing my brain and I am sure I am just missing something

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Programming :: Effective Debugging Or Improving Ones Debugging Skills ?

May 21, 2009

Does anyone know how can one improve his debugging skills or how can one narrow down the problem and try to get to the solution ASAP.Or rather how once should approach a problem.I know this is a bit vague question but I want to know how you people approach?

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Software :: Debugging Clients And Servers?

Feb 17, 2011

I am trying to find some ideas on debugging clients and servers. For example, what would be -really great- is to

1. start a debugger with a server (running on a port)

2. start up the client (using a debugger).

Run the client and then trace the processing from the client side to the server side.

How can one accomplish this?

I have downloaded valgrid and Qt Creator - but not sure how one can use both.

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Programming :: Unix Programming - Single Thread Server Can Support Exactly 2 Clients At Once

Sep 28, 2010

A simple TCP based chat server could allow users to use any TCP client (telnet, for example) to communicate with each other. For this question you should consider a single process, single thread server that can support exactly 2 clients at once, the server simply forwards whatever is sent from one client to the other (in both directions). Your server must not insist on any specific ordering of messages as soon as something is sent from one client it is immediately forwarded to the other client. As soon as either client terminates the connection the server can exit

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Server :: Server For Shell Programming On Windows (XP) Clients?

Jan 9, 2010

I have to have a Linux server for shell programming on Windows (XP) clients

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Programming :: How To Compile / Simple Tutorial For Making Simple Program

Oct 7, 2010

i'm a college student studying pc programing, and i was given today a special work and i have to program using miranda... which i've never used it >.< can anyone give me a hand to where to download, how to compile, and a simple tutorial for making a simple program or something?

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Programming :: Simple Multi-threaded/forked TCP Listener/server?

Aug 12, 2010

For quite some time now, I've been trying to implement a multi-threaded or forked TCP server to perform the following action:1) Listen for new connections on all ip addresses on a specific port.2) Wait for a new connection to arrive3) When a new connection coms in, fork or thread to free up the listening process so it can go back to #2.When handling a client after it's been forked/threaded4) Get the connected client's ip address.5) Perform some in-house processing;6) Read the data sent from the client (checking for http connections)7) Perform some more processing;8) Write some data back to the client based on the above processing9) Close the socket/thread/forkI've tried implementing an solution similar to the multi-threaded example show here; as well as looking at the CPAN solutions Net:aemon and POE::Component::Server::TCP but these don't seem to give me the information needed.The active-venture solution provides me with what I need, but randomly exits without reason/error and when attempting to change the 'for' loop to a 'while' loop, it keeps throwing up different errors.

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Programming :: Debugging Multithreaded Application?

Aug 23, 2010

i need to debug a application which is using many threads. i am using eclipse with GDB debugger but it is not possible to debug it since it has a lot of different threads and i can not not debug it as wre debug in case of single thread(main) . So i would like to know, is there a way to debug such an application, if there is some tutorial that would be nice to know.

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Programming :: GDB (No Debugging Symbols Found)

Oct 19, 2010

I'm running gdb across a network using gdb server. I've got it up and running. However I can't see any source or variables for my code (in ddd /gdb). At start up gdb says (no debugging symbols found). I've got a g in my make file,
CPFLAGS = -Wall -Os -g -pedantic

I've tried loading symbols in using "symbol-file testarm", this sort of works in that I can view symbols but not names, e.g. if I ask dd to show x y and z, rather than
x = 10
y = 20
x = 30

It says:

Also ddd does not show anything in the source window, is there a way I can get it to show this? I think it's because I've started ddd with ddd arm-linux-gdb, as I'm calling a crosscompiler gdb. So can I tell ddd to point to the correct folders? What commands I need to set in gdb/ddd to view variable names (it's hard to keep track when it bunches them all together) and how to view my source code.

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Programming :: Switch Between Processes When Debugging With Gdb?

Feb 11, 2011

How to switch between processes when debugging with gdb?

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Programming :: Debugging GTK + Programs Hangs The System?

Oct 28, 2010

A thread-aware version of gdb receives a system notification when a thread starts in the app it is debugging. GTK+ has hidden threads associated with loading icons into menus. So trying to debug a GTK+ program, even one that is apparently single-threaded, can produce a deadlock between gdb, the app and XWindows. The app (actually GdkPixbufLoader) grabs the focus, the mouse and the keyboard and then starts a thread when a menu is opened. If gdb has trouble with threads, it leaves the app blocked but still holding the mouse, et. al. Then you can't talk to gdb or any other GUI interface. To make gdb happy, all GTK+ apps need to be linked with -pthread, if you have the source. If not, gdb cannot be used. In order to break the deadlock, you need a non-GUI shell. If your /etc/inittab starts agetty, mingetty, or the like, and you can get to it with <CRTL><ALT><F3...F6>, you can do a kill -KILL <pid> on the offending app, recover and then go back to XWindows with <CTRL><ALT> <F1/F2>. Otherwise it's reboot time.

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Programming :: Debugging Kernel Binaries And Modules

Jun 13, 2011

I need to debug "ls". I downloaded coreutils and compiled them in debug mode."ls" uses readdir() kernel API to fetch files/directories from a file system. readdir() fetch data from any file system (suppose FAT or ext3).I have debug version of FAT/ext3 and installed, I also have debug version of coreutils (ls) as well.Now I want to debug from "ls" to "FAT/ext3 readdir()".How to do that?

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Programming :: Debugging Nasm Source Code ?

Dec 5, 2010

I found on the Internet a rough suggestion to debug code which says to add a line:

An example shows this lists the lines of source that do work.

I do not know where these lines are supposed to go and whether the "notdeadyet" should be a call to a subroutine or what. I only found that "%define" is used to link to external files, so I am confused because what I tried did not work.

(I am unable to use (and learn) any debugging tool for another few weeks and I'd like to progress on this If I can.)

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Programming :: Debugging QT Project Through GDB In Command Line?

Jan 31, 2011

First step will obviously be to compile the QT project with -g option, but how to do that through command line?

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Programming :: Gdb Debugging Exec From Child Process?

Jul 14, 2011

Im using gdb for debugging my application.. I was able to debug child process(when fork comes) .. and in child process we have an exec call to .... So the problem is, when the control come to exec , the exec process is executing at a time... I could not debug the exec. process... error is stack curruption due to same frame So, is there any way to debug the exec process

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Programming :: Make File Debugging Racking?

Feb 24, 2010

I have an environment where i have recursive make files (that is one main and in each directory of a project a with rules for that directory).Since i'm not the one who wrote it i'm not familiar with it. I would like to explore when i run certain targets how the rules work, which files cause dependency rules to work and why. Also i would like to know ALL the targets that are available to me. i couldn't find any way to 'debug' makefiles or to put it in such debug mode that i see all the information i need when i run a certain target.

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Programming :: Working With C++ And Autotools - Debugging Application ?

Mar 22, 2010

I have started to work with c++ and autotools.

I mainly maintain an application and a shared library as a hobby.

Nothing professional yet, because I want to understand the best practice strongly recommended by advanced professional programmers.

I check out my sources into $HOME/repository and svn creates:

Where I get c++ sources/headers + and

Now I need to understand what is considered as a good practice for debugging application, either A), B) or something else.

A) install application and its dependency with:



And then I debug the application in the place it was built. [$HOME/repository/app/src/]

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CentOS 5 Server :: 5.5 Is Not Supporting My Printers

Oct 13, 2010

I have CentOS 5.5. server on 2 raid 1 drives .The system is a quad core Intel CPU with 2GB RAM.Printers:-
HP p1006 laserjet
HP multifunction 5600
Canon prixma ip3000
Canon prixma ip4500

I cannot get any of these printers to work on this server.

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Ubuntu :: Script Through Multiple SSH Clients?

Sep 22, 2010

How do I start a script on an ssh server which then starts another script on another ssh server?

Long Explaination I would love to be able to connect to a server with ssh and start a script there which sends a magic packet to my client and waits till it answers the ping. This script is already working, without any problems. After the client started I would love to be able to ssh into the freshly booted client and start another script that starts a Virtual Machine and waits for the ping to answer. The script is working, but how do I start the second script directly from the first one? Best thing would be if I wouldn't have to put in the ssh password again (as it is the same user and the same password).

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Programming :: Debugging Shell Script With A Variable Expansion?

Jan 20, 2011

What I am trying to accomplish is a way to read only the lines that have been added to the file mylog0 since the last time the script looped (5 seconds). I am open to new suggestions too, I have been stuck on this little script for a few hours already.

Code: #!/bin/bash


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Software :: OpenVpn Multiple Clients Gets The Same Client Ip

Mar 9, 2010

I'm using openvpn-2.0.9 with gui-1.0.3 which is set up on windows xp machines(for server and clients) when i set up the server and one client it connects well and i can work without a problem. but when the second client connects it gets the same ip address of the client1, so that both clients can't work at once.

my server and client config files are as follows.

server-configuration file

client1-configuration file

client2-configuration file

I've tried by changing many settings such as server-bridge and all but couldn't find a solution for the problem.

By the way when connected server gets and every clients get same ip as

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Ubuntu :: Kernel Bug - Multiple Mail Clients Crashing 10.04?

Aug 18, 2010

Over the past week or so, I've posted a few message about what looked like general stability problems in lucid, then problems specifically with Thunderbird.

Today I found it isn't just Thunderbird. I tried Claws Mail and Kmail, and all of them exhibit the same symptoms as Thunderbird:

- The app randomly hangs, crashes or stops connecting to the mail server.

- Quitting the app randomly takes down other applications. (Uh-oh -- modern OSs are supposed to prevent one application from corrupting another.)

- Once the problems start, any application is likely to have stability problems -- e.g., this morning, when Kmail started buggering up, I launched the software center to uninstall it and the window never appeared. A box showed up in the window panel at the bottom of the screen at first, but when it was time to draw the window, kaboom.

(I'm currently not using Evolution because of issues with syncing message deletion back to the server. Plus, at least once, Evolution lost its connection to the mail server. I don't remember serious instability with it, but I wasn't looking for the instability either. It might well be just as bad as the others.)

So, we have an issue triggered by multiple applications, and the issue is not limited to one unstable process on the machine (one unstable process makes other processes unstable). That smells like a kernel bug.

I'm wondering if anyone else has seen anything like this? I'm using the amd64 version on a MSI A6200, Intel Core i3 processor. I'll have to doublecheck the kernel version. When I installed the OS, it was (something-something).21 and now (after the first round of automatic system updates) it's .24 - "something-something" is whatever the standard kernel is when you download the amd64 CDROM image.

As long as I'm not running a mail client (apparently, any mail client), the system is stable. So it looks very much like there is something that mail clients do, which other applications tend not to do, which is broken.

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Networking :: Xinetd To Fork New Instances Of Foo So Multiple Clients Can Connect To It

Aug 3, 2010

Suppose I have a server, foo, that runs on port 5555. I can make one connection to it at a time on that port. I want xinetd to fork new instances of foo so multiple clients can connect to it.

Here's a configuration entry:

1) How does xinetd fork a new instance of foo when a previous instance is already listening on port 5555? Wouldn't the new process fail to launch because port 5555 is already in use by the previous process?

2) Suppose five clients connect simultaneously, and xinetd forks five instances of foo. When the clients disconnect, does xinetd leave all five instances running?

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CentOS 5 Networking :: OpenVPN Multiple Servers With Clients Access

Dec 27, 2010

what is the best way here? I have like 5 servers, and I want my clients to access each of them, so in case 1 server is down, they can access remaining servers. Also, it will work like user1 chooses the server number and is connecting to a central database, then reply is OK, and he can connect to the server number he wished.

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Ubuntu :: Simple Scan Multiple Page Exposure

Jul 27, 2011

I have an interesting issue with simple scan. When I scan a single page document, the exposure is not very good because there are dark and light areas scattered over the entire document. Of course, one cannot adjust these settings in simple scan as one can with xsane. However, I noticed if I scanned a multiple page document, all pages after the first seemed to be more consistent and the exposure was fairly good (exposure here referring to all the aspects accessable in xsane such as brightness, contrast, gamma, etc.)

So I tried a little experiment. I scanned a single page document as if it were a multiple page document by scanning the document multiple times in the same session.The same thing occurs as if one were scanning a multiple document: the first page is mottled, but all pages after are much better scans. What is happening here?

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Ubuntu Servers :: Simple Q Multiple Apache Users And Remote Administration

Feb 7, 2011

how one professionaly would solve the security and administration for the multiple webadmins, but firstly I give some general information.I spent 2 days searching and there are alot of good guides but I dont see my specific questions answered, not so I can understand them atleast.I have Ubuntu 10.10 64bit server edition installed.I am educating myself and am new to linux but use vmware and have installed Gentoo multiple times and a copy of Ubuntu server. This server is going to be setup on the 64-bit 10.10 Ubuntu virtual machine.

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Programming :: Copying Multiple AVI Files To NAS Server

May 18, 2009

I am working with DM355 target board. Here we record. The video coming from IP cameras. Now I have to write c program for copying. The recorded avi files with date and time to NAS server using scp. I wrote a script to copy single file to NAS server.

DATE=$(date +%Y%m%d_%H_%M_%S)
mv Camera1.avi Camera1_$DATE.avi
scp Camera1_$DATE.avi root@
mv Camera1_$DATE.avi Camera1.av

But I have to write c program for copying multiple avi files with Date and Time to NAS server.

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Programming :: Closing Multiple Client Sockets In Server ?

Nov 30, 2010

I have written a server application which has select for both incoming new client connection requests and incoming data from client. I am able to process incoming connection requests and client data.

For example, server has 8 clients connected to it. If client 3 disconnects from server, how will server come to know this client has disconnected and to close its client socket fd gracefully? Does server's select get data on that client socket fd as 'close' data or any error code in recv() function that notifies server to close this client socket fd? Also if client disconnects abruptly without sending close request to server, how should server handle this? Does server get "EPIPE" error?

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