# PSEUDOCODE
...

our $MAXTHREADS = 5;
our @aryItems : shared;
...

main();

sub main {...}

sub process {
        my $threads = 0;
        my $files = (@aryItems);

        if ($files > $MAXTHREADS) {
            $threads = $MAXTHREADS;
        }
        
        initThreads($threads, ...);
...
}

sub initThreads {
    ...
    my $threads = 0;
    ...

    ($threads, ...) = @_;

    our @threads = ();
    
    for (0..$threads - 1) {
        push @threads, threads->new(
                                   \&Foo::run,
                                    id => $_,
                                    ...
                                   );
    }
}
...
####
Foo class
####
package Foo;
use threads;
use threads::shared;
...

sub new{...};
sub run{<processing and locking code goes here>};