#!/usr/bin/perl
 
use strict;
use warnings;
 
print "Begin Main\n";
 
## we store the child process in this array
my @childArray;
 
## path to the files go in this array. It could be one or a dozen
## and is determined by another process
our @fileArray = qw(fileone.txt filetwo.txt filethree.txt);
 
## This is the number of forks we will allow
my $forkCeiling = "5";
 
my $pid;
my $fileName;
 
for ( my $forkCount = 1; $forkCount <= $forkCeiling; $forkCount++) {
        $pid = fork();
        if ($pid) {
        
        push(@childArray, $pid);
        } elsif ($pid == 0) {
                
                # call the download subroutine and pass the number of forks, parent pid and array
                print "Sending fork number $forkCount to the \"process files\" subroutine...\n";
                
                my $file = shift(@fileArray);
                
                print "DEBUG: $file \n";              
                
                procFiles($forkCount, $$, $file);
                
                exit 0;
               
                    } else {
                    die "couldnt fork: $!\n";
                   }
 
 
 
}
 
## we will stand by here and wait for each of those pids to complete
## The log entry for each fork will go here.
foreach (@childArray) {
        my $procId = waitpid($_, 0);
        print "LOG:  process number $procId\n";
}
 
print "Main Terminated\n";
 
 
 
sub procFiles {
 
 
   ## simulate delay in processing dissimilar files 
   srand();
   my $minDelay = 1;
   my $maxDelay = 2;
   my $timeDelay = int(rand($maxDelay)) + $minDelay;
   
   ## get the fork number, process id and filename 
   my $forkCount = $_[0];
   my $procId = $_[1];
   my $fileName = $_[2];
  
   
   ## get the process id for this fork
   my $processIDnum = shift;
       
   ## sleep $num;
   print "Completed child process ($procId), fork number $forkCount, file name $fileName\n";
       
   ## retun the process id, which will be picked up
   return $processIDnum;
}