#!/usr/bin/perl

use warnings;
use strict;
use Uber qw / client_list /;

use Parallel::ForkManager;

my $max_forks = 2; # Changed to 2 just to see if it would go to the next one...
my $clients   = client_list();

my $fork = new Parallel::ForkManager($max_forks);


for my $client ( @$clients ){

    $fork->start( $client->{id} ) and next;

    do_something( $client->{id} );

    $fork->finish;
    
}

sub do_something {
    my $client = shift;
    system( "perl", "C:/Path/To/Folder/process.pl", "$client" );
}

$fork->wait_all_children