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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10
votes
3answers
8k views

How can I find a memory leak of a running process?

Is there a way, I can find the memory leak of a running process? I can use Valgrind for finding memory leaks before the start of a process. I can use GDB to attach it to a running process. How could I ...
3
votes
1answer
1k 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 ...
1
vote
0answers
23 views

can two android devices in different network(3g) comunicate themselves with ssh connection?

I have two rooted android devices with different isp(i use different 3g connection for them) and created a double ssh connection(i can with a public ip server)comunicating both to this server(i have ...
0
votes
0answers
15 views

Strange PFN read from pagemap

I m trying to find the physical page to which a range of virtual addresses are mapped in a piece of C code that I ve written. I m using the /proc/self/pagemap to read the mapping. I ve used the code ...
3
votes
0answers
26 views

Linux application development and signal handling

Currently I am having problems with my users complaining about the termination of my application. Under some (seemingly arbitrary) conditions and desktop environments the app is not terminated and ...
-1
votes
0answers
10 views

Socket test failed on Tru64 v4.0

I need to use sockets on DEC Unix v4.0 to run a client-server app. When I run my app I get an error that says "socket not open or closed" After that error I am going to go to test socket. I ...
0
votes
0answers
13 views

How to find offset of st_link? [migrated]

What number we have to add to the base address of struct stat to find the offset of st_nlink in fstat system call ?
0
votes
0answers
16 views

Compile project with cmake for OpenBSD 5.9

I'm writing a shell and have compiled and run it with Ubuntu. It previously built and ran with OpenBSD 5.9 earlier, but now I get compiler error that I don't understand. $ make [ ...
0
votes
0answers
51 views

Where are the definitions for the prototype declarations in <bsd/stdlib.h>?

I have a C program on Ubuntu 16.04, in which I would like to use arc4random_uniform. typedef unsigned char u_char; #include <bsd/stdlib.h> int main () { return (int) arc4random_uniform(100); } ...
1
vote
0answers
84 views

What is stored in the first memory address' of the OS? Why can't I print the contents? [migrated]

So this is solely for my own curiosity, I wanted to go through every memory address from 0x000000 all the way to the last address of my hard drive. So I wrote this C snippet: #include <stdio.h> ...
0
votes
1answer
28 views

Checking that $((a * b)) evaluates in my own shell [closed]

POSIX seems to define that a shell should be able to evaluate like a calculator the expression $(( a * b)) where * is a binary operator +, - or *. I programmed such a calculator for my own shell and ...
1
vote
1answer
40 views

How to read from another terminal?

I opened two terminals (/dev/pts/1 and /dev/pts/2) and started my application from /dev/pts/1. I want to read in real time from /dev/pts/2 but my code doesn't work: actually some of the symbols are ...
0
votes
0answers
34 views

set the execute bits in C [migrated]

I am writing a program which requires me to create a file using standard fopen fprintf fclose calls. I want to set the execute bits. I can do this with chmod but this seems overkill. For the life of ...
5
votes
2answers
17k views

Default stack size for pthreads

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

Can all of fork(), exec() and system() be wrong? [closed]

I understand why it could be less than best practice if I write C code that executes shell commands by calling system() and that it's better to use exec and fork but then a very experienced C ...
0
votes
0answers
9 views

Is editline tab completion supposed to work? [migrated]

Is there a way for libedit (editline) to do tab completion if I use editline for a small shell? It seems that rl_parse_and_bind is not available if I include histedit.h - why doesn't it work? int ...
213
votes
4answers
76k views

Why is FreeBSD deprecating GCC in favor of Clang/LLVM?

So I was surfing the net and stumbled upon this article. It basically states that FreeBSD, starting from Version 10 and above will deprecate GCC in favor of Clang/LLVM. From what I have seen around ...
1
vote
1answer
56 views

Using Named Pipes in Bash created in a C Program

I have a C code that takes a rather large input. At every iteration, it processes a small chunk of it and it should send that processed chunk to S3 using curl. In the end, it will generate a number of ...
3
votes
3answers
201 views

POSIX compliance of the cd program?

Is globbing and shell expansion same thing? I'm learning C by writing a custom shell and I'm also learning POSIX. Now I wonder if it is POSIX compliance that cd - takes you back and that ~ means home ...
2
votes
2answers
53 views

How can I find out what linker flags are needed to use a given C library function?

Running example C code is a painful exercise unless it comes with a makefile. I often find myself with a C file containing code that supposedly does something very cool, but for which a first basic ...
1
vote
2answers
42 views

How to extract a function from file? [closed]

I am looking for a command to extract a C function from my code. It would be something like: $ grep -func "MyFunction" foo.c int MyFunction(int i) { return i+1; } I know we can extract it with ...
0
votes
0answers
24 views

Build location-independent GCC binaries

I have some problems with GCC. I want a portable version of GCC because the PC I use for programming cannot be connected to Internet due to some driver issues. So, I read an article on how to compile ...
0
votes
0answers
11 views

Error with libraries after setting up Code::blocks to work as an arduino IDE

First of all I apologize in advance if this is the wrong community, you're welcome to advise me another one to post. I followed this guide: ...
0
votes
0answers
11 views

Error occured with USB modem

I have MPC8309 Tower Board and connected USB Modem to it and then established Async PPP on Modem, now I started applying ping from different terminal from my laptop by applying nat commands and ...
0
votes
1answer
77 views

Maintaining single binary across Debian distributions

We are currently migrating our system from Debian 6 to 8. The agenda is to try to maintain single binary across OS platforms (x86 based) However, I tried running a Debian 8–compiled binary in ...
1
vote
1answer
75 views

What is the number at the top for the results for ls -l? [duplicate]

When you type in ls -l, there is a number on the first line labeled "total 22037"? What does this number mean? I am attempting to write my own version of ls -l( in C), and how do I get this value or ...
0
votes
1answer
18 views

Busy /dev/gpio. I can shared it?

I need shared one device between two C applications. This device is a buzzer. I've try open this with O_NONBLOCK flag, but result is same: device or resource busy. Is there any possibility to use the ...
1
vote
1answer
81 views

Why do the Linux kernel headers contain references to nonexistent headers?

I'm trying to build IBCS (source here) on Ubuntu 15.10 (Linux 4.2.35). This module is obviously pretty old, because its CONFIG.i386 file gives gcc an option -m486, which doesn't exist anymore, but ...
0
votes
0answers
21 views

How to call a device's power management methods in another way than during suspend to ram?

Let us consider the e1000e driver for an Ethernet card. This driver provide two power management methods .suspend and .resume to respectively turn off and turn on the card. Those methods are naturally ...
1
vote
1answer
58 views

pkg-config output not working with makefile?

I'm trying to run the makefile, shown in this repo, which is a simple Wayland client. But when I run make, it seems that the output of $(WAYLAND) is blank, and it fails to compile due to not being ...
1
vote
0answers
45 views

Is the (Free)BSD Codebase ANSI Compliant?

Google does not seem to shed any light on this topic - But the question is quite simple: Is the FreeBSD (Or any BSD) CodeBase ANSI (c89) Compliant, or does it use c99, c11 or non-standard features ...
3
votes
1answer
51 views

No stdlib in UNIX v7?

Browsing through the v7 UNIX Sources I noticed there is no "stdlib" directory - further more using a v7 UNIX Emulator, there is no such file as <stdlib.h>. However functions like exit() and ...
0
votes
1answer
146 views

how to define the top dir in automake system?

I usually use a typical steps to generate the makefile, and firstly I use the "build.sh init" to generate the configure file, and then I use "configure" to generate the makefile with makefile.am file. ...
1
vote
0answers
24 views

Unable to establish PPP on USB dongle?

I have USB Dongle and i am willing to setup ppp through the dongle. I have done following steps to setup ppp. 1.When i plugged the dongle into Ubuntu 14.04. It has been detected as the Mass ...
2
votes
1answer
40 views

non-reentrant libraries in shared memory?

I found this Q&A saying shared libraries can be shared between processes using shared memory. It seems like it would be impossible, though, to share code between processes without some pretty ...
1
vote
0answers
22 views

I2C Read unexplained data [closed]

I am trying to communicate with a PHY device using I2C primitives (read()/write()) in C language in user space. And i am getting some unexplained output in my program. First, the bus number is 2 and ...
0
votes
2answers
44 views

Parent process always printing output after child

Consider the following code running under Solaris 11.3: int main(void) { pid_t pid = fork(); if (pid > 0) { printf("[%ld]: Writing from parent process\n", getpid()); } if ...
1
vote
1answer
42 views

Location of executable file formed after compiling a C program

I have compiled my C source code using: gcc filename.c It got compiled, but I cannot see the executable in the same directory where my source code is. But when I compile my program using: gcc ...
1
vote
1answer
843 views

Cannot find -lgcc

I'm trying to compile my next basic c program after hello-world. This contains two supporting modules. I have Ubuntu running in a VM through VirtualBox on a mac. Everything is up to date but I ...
1
vote
2answers
38 views

Run an executable as a service on a port

I have a C program (say a simple Queue system) which I compile and get an executable file. I want to run this executable as a service on a specific TCP port on a CentOS system which I can connect to ...
0
votes
0answers
155 views

Building Handbrake on Debian Jessie

I have found a web site that explains how to install Handbrake 0.9.9 on Jessie. The explanations there seem a bit outdated, because it advises to use SVN to get the sources, but Handbrake has switched ...
0
votes
1answer
54 views

How does one establish SIGRTMIN at run-time?

Reading up on signal(7) I can see that now: two, but once: three; signal numbers past 31 are reserved for use by the Real-time signal system and should not be used: Real-time Signals Linux ...
7
votes
2answers
10k views

How does copy-on-write in fork() handle multiple fork?

According to Wikipedia (which could be wrong) When a fork() system call is issued, a copy of all the pages corresponding to the parent process is created, loaded into a separate memory location by ...
1
vote
3answers
105 views

Trouble with creating an empty file using C programming language in UNIX environment

I have recently started programming in UNIX environment. I need to write a program which creates an empty file with name and size given in the terminal using this commands gcc foo.c -o foo.o ./foo.o ...
0
votes
0answers
8 views

GDB not copying desired string (Buffer Overflow attempt)

Ok so I am trying to learn about buffer overflows and there is this simple program that is vulnerable of a BoF because it copies the first argument into a buffer of 5 characters. In the source code, ...
0
votes
1answer
63 views

How can I succesfully call the execv function? [closed]

I am trying to make a program that will copy file1 into file2 the following way: cp -i -p file1 file2 Now I call my executable copy and so by calling copy file1 file2 It will do the same thing ...
6
votes
2answers
80 views

Get header of the C function from BASH

I want to get the header(s) that I need for a given C function - e.g. when I want to see what to include when I want to use fork(), I can type out man fork and see that it's #include <unistd.h>. ...
2
votes
2answers
74 views

Minimal Busybox/Linux Installation - Won't Run C

I'm trying my hand at creating a very minimal custom Busybox/Linux distro, a task that is admittedly above my head, but I figured I'd give it a shot. My issue is that whenever I try to run a C program ...
0
votes
1answer
51 views

How do kthreads actually work?

Need to implement DHCP server in kernel space. It's supposed to be a multithreading server, and I think I should use kthreads ( I'll be glade if you know better decision ). However I can't understand ...
-2
votes
2answers
15 views

Is the flag treated as string in c command argument? [closed]

say I have the following: #include <stdio.h> #include <string.h> int main(int argc, char *argv[]){ if (argv[1] == "-s") { printf("success\n"); } else{ ...