Sponsored Content
Full Discussion: Fork()
Top Forums Programming Fork() Post 302386636 by thegeek on Wednesday 13th of January 2010 02:40:08 AM
Old 01-13-2010
Yes, you are right.

An example to clarify the matter better,

Code:
use strict;
use warnings;

print "PARENT 1: $$\n";
my $pid = fork ();
if ( $pid )  {
    print "Parent of 1st fork $$\n";
} else {
    print "Child of 1st fork $$\n";
}

my $next_pid = fork ();

if ( $next_pid )  {
    print "Parent of next fork $$\n";
} else {
    print "Child of next fork $$\n";
}

And its output,
Code:
PARENT 1: 27844
Child of 1st fork 27845
Child of next fork 27846
Parent of next fork 27845
Parent of 1st fork 27844
Child of next fork 27847
Parent of next fork 27844

It is so clear that, the first process id is: 27844, which gets forked into another as: 27845.

Then the next is two parents: 27844, 27845 which gets two childs as: 27846, 27847.
 

10 More Discussions You Might Find Interesting

1. UNIX for Dummies Questions & Answers

Fork

What is a fork? Why would one create a fork? What are the advantages and disadvantages of using a fork? Please advise. Thank You. Deepali (5 Replies)
Discussion started by: Deepali
5 Replies

2. Programming

fork() fd

I run this code, actually I want to both processes print the message from "data". But only one does. What happens? Anyone can help? #include <stdio.h> main(){ int fd, pid; char x; fd = open("data",0); /* open file "data" */ pid = fork(); if(pid != 0){ wait(0); ... (2 Replies)
Discussion started by: Herman
2 Replies

3. Programming

fork()

#include <stdio.h> #include <string.h> #include <sys/types.h> #define MAX_COUNT 200 #define BUF_SIZE 100 void main(void) { pid_t pid; int i; char buf; fork(); pid = getpid(); for (i = 1; i <= MAX_COUNT; i++) { sprintf(buf,... (2 Replies)
Discussion started by: MKSRaja
2 Replies

4. Programming

Fork or what?

Hello all. I'm developing a filetransfer application, which is supposed to work sort of like dcc, with multiple transfers etc. Now i wonder what the best way to manage the transfers is. Should i fork() for each new transfer, hogging loads of memory or use pthreads? Maybe I can use select to see... (0 Replies)
Discussion started by: crippe
0 Replies

5. Programming

Fork ()

hi all About this code for (i = 1; i < n; i++) if ((childpid = fork()) <= 0) break; I really can't understand the output . and the way fork () return the value . how about the process Id ,the child process Id and the parent ID in this case so please answer me soon (5 Replies)
Discussion started by: iwbasts
5 Replies

6. Programming

fork() help

Hi everybody, I wanna write a code to understand how fork works. my target -------------- -Parent creates a file(called temp) and writes into this file "1".Then it closes the file. -Then parent creates a child and wait until execution of this child ends. -Then child opens the same... (3 Replies)
Discussion started by: alexicopax
3 Replies

7. UNIX for Advanced & Expert Users

Fork and \n

Hi, I wrote a simple program for understanding the fork command. The code is as below int main(void) { fork(); printf("hi 1 \n"); fork(); printf("hi 2 \n"); fork(); printf("hi 3 \n"); } I am getting a variation in the number of times the printf is called if i remove the \n from each of... (1 Reply)
Discussion started by: xyz123456
1 Replies

8. Programming

Fork and \n

Hi, I wrote a simple program for understanding the fork command. The code is as below int main(void) { fork(); printf("hi 1 \n"); fork(); printf("hi 2 \n"); fork(); printf("hi 3 \n"); } I am getting a variation in the number of times the printf is called if i remove the \n from each... (2 Replies)
Discussion started by: xyz123456
2 Replies

9. UNIX for Dummies Questions & Answers

fork()

I'm trying to run a simple test on how to use fork(), i'm able to execute the child process first then the parent, but how can I execute parent then child..? Thanks! (1 Reply)
Discussion started by: l flipboi l
1 Replies

10. Programming

Fork!

I understand that fork create a child but I need very simple example that make child useful.... I mean how will make the program faster anyone explain with code plz using C plz (2 Replies)
Discussion started by: fwrlfo
2 Replies
IO::Pipe(3pm)						 Perl Programmers Reference Guide					     IO::Pipe(3pm)

NAME
IO::Pipe - supply object methods for pipes SYNOPSIS
use IO::Pipe; $pipe = IO::Pipe->new(); if($pid = fork()) { # Parent $pipe->reader(); while(<$pipe>) { ... } } elsif(defined $pid) { # Child $pipe->writer(); print $pipe ... } or $pipe = IO::Pipe->new(); $pipe->reader(qw(ls -l)); while(<$pipe>) { ... } DESCRIPTION
"IO::Pipe" provides an interface to creating pipes between processes. CONSTRUCTOR
new ( [READER, WRITER] ) Creates an "IO::Pipe", which is a reference to a newly created symbol (see the "Symbol" package). "IO::Pipe::new" optionally takes two arguments, which should be objects blessed into "IO::Handle", or a subclass thereof. These two objects will be used for the system call to "pipe". If no arguments are given then method "handles" is called on the new "IO::Pipe" object. These two handles are held in the array part of the GLOB until either "reader" or "writer" is called. METHODS
reader ([ARGS]) The object is re-blessed into a sub-class of "IO::Handle", and becomes a handle at the reading end of the pipe. If "ARGS" are given then "fork" is called and "ARGS" are passed to exec. writer ([ARGS]) The object is re-blessed into a sub-class of "IO::Handle", and becomes a handle at the writing end of the pipe. If "ARGS" are given then "fork" is called and "ARGS" are passed to exec. handles () This method is called during construction by "IO::Pipe::new" on the newly created "IO::Pipe" object. It returns an array of two objects blessed into "IO::Pipe::End", or a subclass thereof. SEE ALSO
IO::Handle AUTHOR
Graham Barr. Currently maintained by the Perl Porters. Please report all bugs to <perlbug@perl.org>. COPYRIGHT
Copyright (c) 1996-8 Graham Barr <gbarr@pobox.com>. All rights reserved. This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself. perl v5.18.2 2013-11-04 IO::Pipe(3pm)
All times are GMT -4. The time now is 11:22 AM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy