Perl Guru Forums: Need a Custom or Prewritten Perl Program?: I need a program that...: Can Demonstrate simple fork()

CGI/Perl Guide | Learning Center | Forums | Advertise | Login

Site Search: in


	MAIN INDEX	SEARCH POSTS	WHO'S ONLINE	LOG IN

Home: Need a Custom or Prewritten Perl Program?: I need a program that...:
Can Demonstrate simple fork()

auximage
New User

Jan 22, 2003, 2:30 AM

Post #1 of 3 (1176 views)

Can Demonstrate simple fork()	Can't Post

I've been programming in Perl for a while now, but just recently have had the reason to use fork(). I have gone to quiet a few sites, and poured through the multiple books I have on Perl, but just can't get this into my thick skull. I learn by seeing and reversing code (usually).

Anyway, my request. A simple program that would do basically this:

Start a parent, print [Parent]

fork/start child process print [Child]

the child process would sleep for 10 seconds then assign $i =1;

while the child is sleeping, the parent would print "waiting\n";sleep 1; (so i would get 10 "waiting" messages

once $i is assigned 1, child would print [Child End]

parent would print [Parent End]

I apologize if this comes off as a little trivial, but I have been banging my head, fighting zombies, and trying to understand significances of waitpid for about 3 days now. Anyway, any help would be greatly appreciated as I would be able to work through how fork goes through the motions with a simple program like listed above.

davorg
Thaumaturge

Jan 24, 2003, 8:50 AM

Post #2 of 3 (1169 views)

Re: [auximage] Can Demonstrate simple fork() [In reply to]	Can't Post

Something like this perhaps:

Code

#!/usr/bin/perl 
 
use strict; 
use warnings; 
use POSIX ':sys_wait_h'; 
 
if (fork) { 
  # parent 
  print "[Parent]\n"; 
  until (waitpid(-1, &WNOHANG)) { 
    print "waiting...\n"; 
    sleep 1; 
  } 
  print "[Parent End]\n"; 
} else { 
  # child 
  print "[Child]\n"; 
  sleep 10; 
  my $i = 1; 
  print "[Child End]\n"; 
}

--
Dave Cross, Perl Hacker, Trainer and Writer
http://www.dave.org.uk/
Get more help at Perl Monks

auximage
New User

Jan 24, 2003, 11:18 AM

Post #3 of 3 (1167 views)

Re: [davorg] Can Demonstrate simple fork() [In reply to]	Can't Post

A million + 1 thanks to you.

I see that I am going to have to dig a little deeper to understand signal handling.

Again, I can not thank you enough..!!!

Search for (options)

Web Applications & Managed Hosting Powered by Gossamer Threads
Visit our Mailing List Archives