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Top Forums Shell Programming and Scripting Need explanation on Perl Fork Post 302725533 by liyakathali on Friday 2nd of November 2012 10:10:31 AM
Old 11-02-2012
Need explanation on Perl Fork

Hi,

I am breaking my head to understand the below line of code in perl:
Code:
next if $pid = fork;    # Parent goes to next server.
    die "fork failed: $!" unless defined $pid;

Can anyone please explain me in detail as I am a slow learner?

Thanks,
Ali.

Last edited by Franklin52; 03-28-2013 at 04:20 AM.. Reason: Please use code tags for data and code samples
 

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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 v5.16.3 2013-03-04 IO::Pipe(3pm)
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