how to solve producer consumer problem in perl when threads are disabled

[david2008]

Hi all, I want to solve the producer consumer problem in perl as described
here The problem is that the perl i am working on has threads disabled.
How would you connect forked processes so that the producers and consumers could communicate?
Thanks,
David

[BrowserUk]

The simplest mechanism is a shell pipe.

Producer: perl -e"$|++;for(1..10){ printf qq[%05d\n], $_; sleep 1 }"

Consumer: perl -E"$|++; while(<>){ print; }"

Communications:

>perl -e"$|++;for(1..10){ printf qq[%05d\n], $_; sleep 1 }" | perl -E"
+$|++; while(<>){ print; }"
00001
00002
00003
00004
00005
00006
00007
00008
00009
00010

[atcroft]

What have you tried thus far?

The perl IPC (inter-process communication) document describes various methods of interprocess communication in perl, including the use of signals, fifos, pipes, sockets, and semaphores. It also includes examples of bi-directional communications. After reviewing that document, all that should remain is just a small matter of programming. :)

Hope that helps.

[Corion]

I would use one of the many approaches outlined in perlipc.

[zentara]

Something along this line:

#!/usr/bin/perl
# code by pg
use IO::Handle;
use strict;
use warnings;

$| ++;

pipe(PARENT_RDR, CHILD_WTR);


if (fork()) {
   if (fork()) {
       close CHILD_WTR;
       while (my $line = <PARENT_RDR>) {
           print "parent got $line";
       }
   } else {
       close PARENT_RDR;
       for (100..110) {
           print CHILD_WTR "$_\n";
       }
   }
} else {
   close PARENT_RDR;
   for (0..10) {
       print CHILD_WTR "$_\n";
   }
}

[Anonymous Monk]

forks:P

[Anonymous Monk]

As others have already said here ... write the producer, then write the consumer, and connect the two with a shell pipe. The IPC magic, therefore, is handled simply and automagically by the pipe, which appears to each as a simple file, but which will block the reader if there is nothing to read and block the writer if there is nothing to write. Other variations on existing "Unix plumbing" allow for multiple producers and/or consumers to be piped-together. You implement a complicated solution, mostly by avoiding the complexity altogether!