I am using this code to create the threads using fork. This will read all the files in a directory and writes to a log file. Now this code creates th elog file. But some of the files are missed due to overlapping. How can I avoid this using locks

#!/usr/bin/perl
use Parallel::ForkManager;

my $processor = shift;
$tc=5; # threads
$fc = 100; # splits.. each thread should process 100 at a time

my $pm = new Parallel::ForkManager($tc+1);
    $pm->run_on_finish( sub { my ($pid, $exit_code, $ident) = @_; $tmp
+Files[$ident] = undef; } );
    foreach my $i (0..$#tmpFiles) {
      # Forks and returns the pid for the child:
      my $pid = $pm->start($i) and next;

      $SIG{INT} = 'DEFAULT';
      my $filename = $tmpFiles[$i]->filename();
      my $file = IO::File->new("<$filename") or die "Can't open $filen
+ame\n";
      while((my $line) = $file->getline()) {
        last unless defined($line);
        chomp $line;
        my ($dir, $file) = split(/\t/, $line);
        $processor->($dir, $file, $config, $log);
      }
      $pm->finish; # Terminates the child process
}
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