Greetings,

The following is a demonstration using MCE::Loop and MCE::Shared.

MCE::Shared v1.805 or later is required if running via Perl5i on a Unix platform.

use strict;
use warnings;

use MCE::Loop;
use MCE::Shared;

# Configure MCE to run with 4 workers.
# A worker receives 1 item per iteration.

MCE::Loop->init(
   max_workers => 4,
   chunk_size  => 1,
);

# Populate an array with test data.

my @data_files = qw/ file1 file2 file3 file4 /;

# Open a shared file handle to the external cat command.

mce_open my $fh, "| cat" or die "open error: $!\n";

# Process the array in parallel.
# Workers send data to the shared file handle.

mce_loop {
   my $file = $_;
   printf $fh "wid: %d, name: %s\n", MCE->wid(), $file;
} @data_files;

# Close the shared file handle.

close $fh;
[download]

The sample code generates the following output. It may differ depending on which worker obtains data first.

wid: 3, name: file1
wid: 2, name: file2
wid: 4, name: file3
wid: 1, name: file4
[download]

On Windows, replace the mce_open line with the following. This will work if Cygwin is installed on the C: drive. The code works with Strawberry Perl, ActiveState Perl, and Cygwin Perl.

mce_open my $fh, '| c:/cygwin/bin/cat.exe' or die "open error: $!\n";
[download]

Warm regards, Mario.