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)
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)
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)
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)
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)
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)
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)
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
LEARN ABOUT MOJAVE
io::pipe5.18
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)