Sponsored Content
Full Discussion: Parent forking
Top Forums Programming Parent forking Post 302493434 by Corona688 on Wednesday 2nd of February 2011 06:02:48 PM
Old 02-02-2011
I usually find it convenient to give the child its own little section for it to run and then call exit() after so it doesn't run all the stuff below it. Much less clutter
Code:
if(in_the_child)
{
        // runs in the child
        command1();
        command2();
        command3();
        // child quits so it doesn't run parent_stuff();
        exit(0);
}

// Only the parent will run this stuff
parent_stuff();
parent_stuff();
parent_stuff();

Code:
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>

int main(void)
{
        pid_t pid[3];
        int n;

        for(n=0; n<3; n++)
        {
                pid[n]=fork();

                if(pid[n] == 0) // if we are the child, exit immediately
                {       exit(0);        }
        }

        printf("Parent pid: %d\n", (int)getpid());

        for(n=0; n<3; n++)
        {
                int status;
                printf("Child %d pid: %d\n", n, pid[n]);
                // We must wait for the child
                waitpid(pid[n], &status, 0);
        }
}

 

10 More Discussions You Might Find Interesting

1. Programming

Forking in a loop

When I compile this C programme I get different outputs each time I run it Please explain to me whats happening in the code if you can give me a detailed explanation. Because I am stuck with this. #include <stdio.h> main(){ int i = 0; printf("I am the... (1 Reply)
Discussion started by: manjuWicky
1 Replies

2. UNIX for Advanced & Expert Users

Forking

When I compile this C programme I get different outputs each time I run it Please explain to me whats happening in the code if you can give me a detailed explanation with the schedular functionality it will help a lot. Because I am stuck with this. #include <stdio.h> main(){... (3 Replies)
Discussion started by: manjuWicky
3 Replies

3. UNIX for Dummies Questions & Answers

forking and killing parent processes

Hi everybody, I'm having some problems wiriting a program in UNIX using the "fork" and "kill" system calls. I have to create a C program P0, which creates 9 other processes P1, P2, ..., P9, where P0 is the father of P1, P1 the father of P2, and so on. All the processes contain an infinite... (0 Replies)
Discussion started by: davewilliams20
0 Replies

4. Programming

forking a new process

Hi I'm currently working with C on UNIX (HPUX) and need to be able to fork a seperate Java process from within a running C process. I can run the following code from the command line via a script but am having difficulty getting it to work from within the code. I am trying to use execl. Is... (4 Replies)
Discussion started by: themezzaman
4 Replies

5. Programming

forking process.

#include <stdio.h> #include <sys/types.h> #include <unistd.h> int main() { pid_t pID; int i; for (i = 0; i < 3; i++) { pID = fork (); if (pID == 0) { printf ("Value of i --> %d... (2 Replies)
Discussion started by: kymthasneem
2 Replies

6. Shell Programming and Scripting

full path of a file situated either in parent's dir. or parent's parent dir. so on...

hi experts(novice people can stay away as it is no child's game), i am developing a script which works like recycle bin of windows. the problem i am facing is that when ever i am trying to delete a file which is situated in parent directory or parent's parent directory i am unable to... (1 Reply)
Discussion started by: yahoo!
1 Replies

7. UNIX for Advanced & Expert Users

Forking a new process without parent dependance

hi, I want my program to fork a new process and then I want to kill the parent process. The parent program before dying will issue a SIGTERM to all its childs. Which eventually kills all Children. I cant handle the SIGTERM at the child level.:( What I was thinking of was the Parent... (3 Replies)
Discussion started by: tyler_durden
3 Replies

8. Shell Programming and Scripting

Forking and Pinging

Keep in mind that I haven't done Perl scripting for a LONG time, so I'm quite rusty. This is what I would like to do: - using fork, create 3 or 4 processes to read 3 or 4 different text documents containing server names or IP addresses - in each of those processes, Perl will ping each of those... (7 Replies)
Discussion started by: kooshi
7 Replies

9. Shell Programming and Scripting

forking a child process and kill its parent to show that child process has init() as its parent

Hi everyone i am very new to linux , working on bash shell. I am trying to solve the given problem 1. Create a process and then create children using fork 2. Check the Status of the application for successful running. 3. Kill all the process(threads) except parent and first child... (2 Replies)
Discussion started by: vizz_k
2 Replies

10. Programming

need help in forking

I have an input file with contents like: 5785690|68690|898809 7960789|89709|789789 7669900|87865|659708 7869098|65769|347658 so on.. I need to pass this file to 10 parallely running processes (forking)so that each line is processed by a process and no line is processed twice and write the... (1 Reply)
Discussion started by: rkrish
1 Replies
preap(1)                                                           User Commands                                                          preap(1)

NAME
preap - force a defunct process to be reaped by its parent SYNOPSIS
preap [-F] pid... DESCRIPTION
A defunct (or zombie) process is one whose exit status has yet to be reaped by its parent. The exit status is reaped via the wait(3C), waitid(2), or waitpid(3C) system call. In the normal course of system operation, zombies may occur, but are typically short-lived. This may happen if a parent exits without having reaped the exit status of some or all of its children. In that case, those children are reparented to PID 1. See init(1M), which periodically reaps such processes. An irresponsible parent process may not exit for a very long time and thus leave zombies on the system. Since the operating system destroys nearly all components of a process before it becomes defunct, such defunct processes do not normally impact system operation. However, they do consume a small amount of system memory. preap forces the parent of the process specified by pid to waitid(3C) for pid, if pid represents a defunct process. preap will attempt to prevent the administrator from unwisely reaping a child process which might soon be reaped by the parent, if: o The process is a child of init(1M). o The parent process is stopped and might wait on the child when it is again allowed to run. o The process has been defunct for less than one minute. OPTIONS
The following option is supported: -F Forces the parent to reap the child, overriding safety checks. OPERANDS
The following operand is supported: pid Process ID list. EXIT STATUS
The following exit values are returned by preap, which prints the exit status of each target process reaped: 0 Successfully operation. non-zero Failure, such as no such process, permission denied, or invalid option. ATTRIBUTES
See attributes(5) for descriptions of the following attributes: +-----------------------------+-----------------------------+ | ATTRIBUTE TYPE | ATTRIBUTE VALUE | +-----------------------------+-----------------------------+ |Availability |SUNWesu (32-bit) | +-----------------------------+-----------------------------+ | |SUNWesxu (64-bit) | +-----------------------------+-----------------------------+ SEE ALSO
proc(1), init(1M), waitid(2), wait(3C), waitpid(3C), proc(4), attributes(5) WARNINGS
preap should be applied sparingly and only in situations in which the administrator or developer has confirmed that defunct processes will not be reaped by the parent process. Otherwise, applying preap may damage the parent process in unpredictable ways. SunOS 5.10 26 Mar 2001 preap(1)
All times are GMT -4. The time now is 05:42 AM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy