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Newbie question on exec,fork, wait,pipe C

 
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Old 06-04-2011
Newbie question on exec,fork, wait,pipe C
Hello everybody.I want to make clear that i am not going to ask from anybody to build my asignement but i have a big problem. I can't seem to find anywhere ONE good example on C about what i am trying to doSmilie.I think it is simple. All i ask is one example, even a link is fine.
So, i want to make a program (Grandfather.c) which will run 2 new existing programs (Father.c,Son.c). Father.c needs to make some calculations.He wakes up Son.c.He sends him two numbers and Son.c adds them and sends back the result.After this Son.c sleeps.
So,to sum up:
1.Grandfother.c runs the 2 programs
2.Son.c builds the pipes and falls asleep
3.Father.c wakes his son and sends him 2 numbers and falls asleep
4.Son.c adds the numbers, sends them back and falls asleep again

I have found several examples that use functions in one program,but i don't understand how to establish connection in 3 programs.Thnak you in advance!!
Last edited by Cuervo; 06-04-2011 at 09:10 PM..
 
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LEARN ABOUT DEBIAN

io::pipe

IO::Pipe(3perl) 					 Perl Programmers Reference Guide					   IO::Pipe(3perl)

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 <perl5-porters@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 v5.14.2							    2011-09-19							   IO::Pipe(3perl)