Im not understanding the output of this program: #include <pthread.h> #include <stdio.h> #include <unistd.h> int i = 0; int main() { while(i<3) { fork(); printf("%d\n",i); ++i; } } The output is: 0 1 2 2 1 2 0 1 2 2 2 1 2 2 Can please someone tell me how i should tackle this issue in order to fu...
Hi I've made a program that create 5 pipes and fork 5 processes in a loop. I've managed to send data from the parent to each child processe, when each child processe is overlapped by another program. Each loop is done in the following manner (parent.c): // Child process - reads from pipe if (childpid == 0) { dup2(fd[0], 0); // re...
The aim of the program is to fork a new child process and execute a process which also has command line arguments.. If i enter "/bin/ls --help". I get the error... shadyabhi@shadyabhi-desktop:~/lab/200801076_lab3$ ./a.out Enter the name of the executable(with full path)/bin/ls --help Starting the executable as a new child process... B...
I' m trying to calculate the total sum of a line of command arguments entered in from the terminal. Thus far, I've gotten to the point where it will print out everything until the very last few digits. I have to make use of fork() to do all of the computation with my companion program. The main program is unable to do any computation for...
I wrote a Perl program which forks and calls a background program in the child process and has a endless while loop which does some stuff in the parent process. Now the while loop should be left when the background program in the child process terminates: $pid = fork(); if ( !$pid ) { exec( "program args" ); } else { while ( 1 )...
#include<stdio.h> #include<unistd.h> #include<stdlib.h> int main(int argc,char **argv) { int fd[2]; pid_t childpid; pipe(fd); childpid=fork(); if (childpid == -1) { perror("Error forking..."); exit(1); } if (childpid) /*parent proces*/ //grep .c { wait(&childpid); //...
Along the same lines as this question - How do I clone all remote branches with Git?, if I have set up a Github repository like so: $ git clone [email protected]:viatropos/spree.git mycart $ cd mycart $ git branch * master $ git remote add origin [email protected]:viatropos/mycart.git fatal: remote origin already exists. $ git remote add myfo...
I know what the fork() does at the higher level. What I'd like to know is this - As soon as there is a fork call, a trap instruction follows and control jumps to execute the fork "handler" . Now,How does this handler , which creates the child process, by duplicating the parent process by creating another address space and process cont...
I'm trying to calculate the sum based off of sets of numbers received from the command line and I use a companion program called worker to due the computation for me. If the amount of numbers received is odd, it will add a zero to the amount of numbers to make the set even. This is the flow of the program in an understandable way(credit...
Hello Can child process use the ptrace system call to trace its parent? Os is linux 2.6 Thanks. upd1: I want to trace process1 from "itself". It is impossible, so I do fork and try to do ptrace(process1_pid, PTRACE_ATTACH) from child process. But I can't, there is a strange error, like kernel prohibits child from tracing their parent...
How can I debug a shared library in the this case: A daemon is checking which job is set to run, if find one, the daemon will fork a process. This process will do dlopen/dlsym etc to use the shared library. The shared library is under my control so I can put one with debug information. While the daemon is not under my control and canno...
I have a git repo. It has been forked several times and many independent commits are made on top of it. Everything normal, like what happens in many github hosted projects. Now, what exact workflow should I follow, if I want to see all that commits individually and apply the ones I like. The workflow I followed, which is not the optima...
Hi, I have a doubt in the following piece of code and its behaviour: #include <stdio.h> #include <unistd.h> #include <stdlib.h> #define N 5 #define nt 1 int pm[N][2],pid[N]; int i,j,size; char s[100]; int count=0; int main() { for(i=1;i<N;i++) { printf("\n i=%d",i); if(pid[i]=fork() == -1) { print...
Hi all, Learning to use the fork() command and how to pipe data between a parent and it's children. I am currently trying to write a simple program to test how the fork and pipe functions work. My problem seems to be the correct use/placement of the wait function. I want the parent to wait for both of its children to finish processing. ...
I'm trying to write a script which creates a number of forked child processes using the pcntl_* functions. Basically, there is a single script which runs in a loop for about a minute, periodically polling a database to see if there is a task to be run. If there is one, it should fork and run the task in a separate process so that the pa...
Situation: I am writing a program in C that maintains a number of threads. Once a thread ends, a new one is created. Each thread forks - the child runs a process via exec() and the parent waits for it to finish. In addition, there is a signal handler thread that waits for signals. If SIGINT is detected then it tells the main threa...
I created a server with Perl under Windows (ActivePerl 5.10.1 build 1006) that forks upon being connected to, accepts some JSON data, and writes it to a database. I am running into a problem after 64 clients connect to the server, the error message being "Resource is not available" when trying to fork. Running this code under Linux I f...
I'm very new to this Parallel::ForkManager module in Perl and it has a lot of credits, so I think it support what I need and I just haven't figured out yet. What i need to do is in each child process, it writes some updates into a global hash map, according to the key value computed in each child process. However, when I proceed to cla...
I'm forking with this code: echo "1. posix_getpid()=".posix_getpid().", posix_getppid()=".posix_getppid()."\n"; $pid = pcntl_fork(); var_dump($pid); if ($pid == -1) die("could not fork"); if ($pid) { //parent echo "2. pid=".$pid.", posix_getpid()=".posix_getpid().", posix_getppid()=".posix_getppid()."\n"; } else { //child $sid = posix...
#include<stdio.h> #include<unistd.h> int main() { int i = 1; if(!fork()) { while(i) { printf("Enter i"); scanf("%d",&i); fflush(stdin); fflush(stdout); } } ...