use strict;
use warnings;

use threads;
use threads::shared;

my @dirs = qw( a b c d e f );
my %hash = map { $_ => shared_clone({}) } @dirs;

my @thrs;

foreach my $dir (@dirs) {
  if (-e "$dir/syn.log") {
    push @thrs, threads->create(\&process_1_file, $dir, "syn.log");
  }
}

$_->join for @thrs;

print $hash{"a"}{"area"}, "\n";

sub process_1_file  {
  my ($dir, $file) = @_;
  open(my $fh, "$dir/$file") or die "cannot open $dir/$file $!";
  while (<$fh>) {
    chomp;
    if ($_ =~ /^area=(.*)/) {
      $hash{"$dir"}{"area"} = $1;
    }
  }
}