C is a general-purpose computer programming language used for operating systems, games and other high performance work and is clearly distinct from C++. It was developed in 1972 by Dennis Ritchie for use with the Unix operating system.

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Linux [admin] How to test pivot_root?

I want to test the pivot_root command line, which moves the root file system of the current process to the directory put_old and makes new_root the new root file system. ...
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0answers
15 views

PAM authentication program in C recognizes only the logged in user [on hold]

I am trying to write a C program to authenticate users using PAM. Here is what I have at present: #include <security/pam_appl.h> #include <security/pam_misc.h> #include <stdio.h> ...
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0answers
18 views

Fault injection into a specific function [on hold]

I want a tool for fault injection in linux C code programs (currently I'm trying to inject faults on Gedit). I want to corrupt function return values, like a bit flip into the binary representation, ...
1
vote
1answer
8 views

snd_rawmidi_open() waits forever - no error message

I am trying to use ALSA for MIDI purposes in C. My problem is, snd_rawmidi_open() sort of "crashes" (waits forever like a while loop) when using valuable arguments : #include <stdio.h> ...
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0answers
25 views

Implementing “cp” command in C language [closed]

How to implement cp command in C language?I know it can be done with the system() function but I want to do it with execl() or some other related functions. For example: ...
2
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0answers
17 views

Make GNU indent break long comments

Is there a way to convince GNU indent to break long comment and change it to multiline comment? Something like this: // Very long comment, longer than 80 characters. Just imagine that. To this: /* ...
2
votes
2answers
68 views

Linux cannot compile without GCC optimizations; implications? [closed]

One can find several threads on the Internet such as this: http://www.gossamer-threads.com/lists/linux/kernel/972619 where people complain they cannot build Linux with -O0, and are told that this is ...
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0answers
14 views

Hardware address of network interface using ioctl on AIX [migrated]

I want to get hardware address of network interface on AIX using ioctl. Like in Linux we get it through: ioctl(sockFd, SIOCGIFADDR, ifr_p); I didn't find SIOCGIFADDR flag in ...
4
votes
1answer
76 views

How to compile programs on Linux systems when I don't have sudo privileges to install the dev dependencies [duplicate]

How should I go about compiling programs that depend on libraries whose development packages (headers and such) aren't pre-installed on the system when I don't have sudo access? In this particular ...
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0answers
22 views

Inotify notifies only single change

I set the inotify_add_watch to watch /dev/disks. The entries in this directory are: by-id and by-uuid. When I plug-in a pen-drive, this directory gets added with two more directories: by-path and ...
3
votes
1answer
82 views

How to create GUIs (such as menuconfig) with lxdialog

I try to generate a menuconfig by my own with the help of lxdialog (source: lxdialog). Unfortunately this is not so well documented as I wished for. Example: So what I did: I included these files ...
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0answers
25 views

CPUFreq Kernel module

I would like to try the CPUFreq module on my board (Marvell Soc based on ARMv7 running a v3.15 linux kernel). My architecture is obviously not supported by the default source code (located in the ...
5
votes
4answers
529 views

chdir(<directory>) doesn't change directory after exiting to shell

I wanted to make a simple C program to change to my project directory. Its content is following: #include <unistd.h> int main(){ chdir("/home/enedil/projects/algo"); return 0; } I ...
0
votes
1answer
54 views

What are the disadvantages of uClibc?

I try to speed up my boot sequence, and somebody recommends to use the uClibc instead of Glibc. I've built an image with it, it gets smaller and faster to boot — but at which cost? Does anyone know ...
3
votes
1answer
95 views

How to programmatically retrieve the GID of a running process

I need to write some C code to check the effective GID of a running process whose PID I know. I've not found any direct way to do this. There are a number of heavyweight kludges I could use, such as ...
2
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0answers
138 views

what device name should I have to give in snd_pcm_open other than “default”

I want to record sound from 2 devices simultaneously: internal mic external usb webcam mic Using pulseaudio sound controller, I set either of these devices as default and could record sound with ...
1
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0answers
64 views

Limit program execution to a list of arguments

I would like that my Unix users can only run a specific command insecurecommand with a controlled list of arguments stored in a file. The only solution I have found at this time is to : Create a ...
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0answers
313 views

GTK3+ and C++ on OSX - “No GSettings schemas are installed” error

I'm trying to run a C++ example with GTK3+ and GStreamer components on OSX. I can gcc compile the source with: gcc -o basic5 basic-tutorial-5.c 'pkg-config --libs --cflags gstreamer-1.0 ...
2
votes
2answers
129 views

How does a parallelized Python program look with top command?

I work on a shared cluster. I've seen people run parallelized c code on this cluster which, when I use top to see what processes are running, are shown to be using (for example) 400% of the CPU, ...
2
votes
2answers
64 views

What is bitwise.c~? [duplicate]

I am new to Linux Debian and I am trying to made a program to experiment bitwise operators. The name of the program is bitwise.c Before compiling the program, I decided to look at the directory just ...
2
votes
1answer
152 views

closing the unwanted file descriptors

I am trying to understand how pipes work . This code snippet is from some website . So my understanding of the program goes like this : When we do pipe(fd) then fd[0]=3 and fd[0]=4 ( assuming only ...
3
votes
1answer
58 views

Is each process considered a thread?

Is a Linux process considered a thread? For example, if I write a simple c program that calls pthread_create to create a new thread in main(), does that mean that I now have 2 threads, one for ...
3
votes
0answers
137 views

How do I use ctags functionality in vim with cscope installed?

When I install cscope by adding the line Bundle 'chazy/cscope_maps to my .vimrc file, my tags menu (g+[) is replaced with a cscope list, which seems to contain a list of files where the tag is called, ...
1
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1answer
1k views

Default stack size for pthreads

As I understand the default stack size for a pthread on linux is 16K. I am getting strange sesults on my 64bit ubuntu install. $ ulimit -s 8192 Also pthread_attr_init(&attr); ...
0
votes
1answer
56 views

Difference between maximum resident set size as reported by /usr/bin/time vs. getrusage?

I ran the command a.out like this: $ /usr/bin/time -f"%M" ./a.out a.out also uses the function getrusage() and prints: printf("%ld",ru.ru_maxrss); where the first ru is the struct. When I run ...
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0answers
75 views

how to get user's last login including the year in C [closed]

I'm trying to write a program that can get the user's last login time. Then i want to do something with the data. eg. check which user havent login for 90 days. So I tried using last command. This ...
9
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5answers
1k views

What is meant by “a system call” if not the implementation in the programing language?

I would like to understand the term "system call". I am familiar that system calls are used to get kernel services from a userspace application. The part i need clarification with is the difference ...
1
vote
1answer
273 views

ioctl: invalid argument for HDIO_GET_IDENTITY

I wrote a program to get the details of hard disk drive using HDIO_ ioctl calls. For writing program, I'm referring Documentation/ioctl/hdio.txt in kernel source(2.6.32). Here is my main part of ...
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0answers
38 views

How to get the authentication status from the last PAM module run

If I have the following PAM stack: auth required default_pam.so auth requisite my_custom_pam.so .... How do you obtain the authentication status from the last/previous PAM module run for use in ...
0
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0answers
142 views

How do I run TinyWM inside Xephyr?

I'm trying to get into Window Manager hacking, so I found TinyWM and tried running it inside a Xephyr window. I tried: Xephyr -screen 1024x768 :1 & DISPLAY=:1 ./tinywm & DISPLAY=:1 scite ...
0
votes
1answer
69 views

Error: Missing newline before EOF - inserted

In my application I am inserting some files in main file. In that there is common header file to all the code files (*.c). This giving me error: D:\New folder\COM_Port_Cont\COM_Port_Task.h(268) : ...
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6answers
1k views

What C library version does my system use?

How can I tell for sure what userland C library my system uses? Possible reasons to need this information include: There's a gigantic source package I am considering downloading which I'm sure will ...
0
votes
1answer
82 views

libext2fs gcc linking error

I am writing a C program which uses libext2fs: #include <ext2fs/ext2fs.h> int main(int argc, char *argv[]) { char *fsname = argv[1]; errcode_t err; ext2_filsys fs; err= ...
4
votes
3answers
369 views

Are there “esoteric” (weird) but standards-compliant C compilers or runtimes?

As we know, the C standard does not specify a lot of details of the implementation, for example value of NULL pointer, order of bits and bytes (endiannes), alignment in structs and of stack ...
1
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0answers
106 views

How to cause memory fragmentation on a Linux based embedded device?

Hardware ARM What am I trying to do: Answer: I am trying to create memory fragmentation on a Linux 2.6.31 based swapless embedded device. Why: Answer:I am trying to port some patches to Linux ...
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2answers
423 views

Writing own daemon. systemd error: Failed to read PID from file: Invalid argument

I'm trying to write own daemon a la very simple MPD (it's operating systems laboratory work). I made it work: it starts like a daemon (output of ps): 1 14877 14877 14877 ? -1 Ss 0 ...
2
votes
1answer
60 views

Can you use LXC through C?

I want to use LXC to 'container' plugins my application is loading. Am I able to do this through C? I have been Googling a lot about it, but there don't seem to be any headers, only scripts that can ...
3
votes
1answer
268 views

How to let a user execute a script owned by root? Setuid doesn't seem to work anymore [duplicate]

I have some bash scripts that I use with the user 'root' to manage iptable rules. The problem is that I want these things at the same time: The script must be owned by root Permissions must be 700 ...
-2
votes
1answer
76 views

How to compile c, c++ and python code as “Released/Final” version? [closed]

I want to know if there are ways to compile C, C++ and Python code in order to not be able to reverse engineering it over Linux or not? I have heard there are some ways over Windows to do it, but I ...
8
votes
7answers
1k views

Possible to find out the sizes of data types (int, float, double, …) on a system, without writing a C program?

Is it possible to find out the sizes of data types (int, float, double, ...) on a Linux system, without writing a C program? Would the results for C same as for C++, and other programming languages ...
0
votes
0answers
137 views

Reading from named pipe freezes when piping tshark output

I'm trying to implement a web prefetching system. The purpose of a system like this is to “predict” future requests and prefetch them. The system builds a predictive model from web navigation logs ...
2
votes
0answers
119 views

How can I compile minix when I make changes in libraries

I am looking for a way to compile minix. The make hdboot command seems to do nothing with the directories under /usr/src/lib. I changed only one .c file in syslib. Do I have to do make world for this ...
0
votes
3answers
107 views

In makefile when do we use .o files?

In the following make file, what is the significance of adding .o files instead of .c files? CC=gcc CFLAGS=-I. hellomake: hellomake.o hellofunc.o $(CC) -o hellomake hellomake.o hellofunc.o ...
5
votes
2answers
341 views

What would I get when sudo a kernel-destructive program?

It suddenly comes to me how easy it will be for a sudoer to crash the kernel, so I tried something like this: #include<stdio.h> int main(){ printf("hello world"); int a; ...
2
votes
1answer
703 views

Error compiling FTDI VCP drivers: Cannot find version.h

driver installation fails of FTDI VCP driver during make install. Running ElementaryOS with kernel 3.11.0-14-generic make install awk: cannot open ...
2
votes
0answers
141 views

Writing to Arbitrary Memory Addresses [closed]

I'm reading "Art of Exploitation 2nd Ed." and I have a question regarding a section on format string attacks. Target program Below code (fmt_vuln.c) is a target program. #include <stdio.h> ...
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0answers
38 views

How to `cat` file with syntax highlight? [duplicate]

In my hello.c: /* Hello World program */ #include main() { printf("Hello World"); } How can i cat this file on terminal with syntax highlight?
1
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3answers
116 views

Is there any manual about C in Linux? If any, what is it?

While I find that we can read some manuals about Library calls (C library functions) & acsii in Linux. But I still do not find any manual about C precedence order so far. So you can recommend ...
2
votes
2answers
221 views

How to make processes not die after its parent dies?

I've been messing with forkbombs and noticed that if I just fork() processes repeatedly, killing the initial process will bring down the whole tree. This is not the case for forkbombs written in BASH ...
3
votes
2answers
101 views

How to write software to compile with external libraries?

I want to code open source software with dependencies. I have skills in C/C++ and a minimum makefile knowledge. But im curious about coding this like ./configure && make stuff and how to ...