#!perl
use strict;
use warnings;
use threads;
use threads::shared;
use Spreadsheet::WriteExcel;

my $workbook  = Spreadsheet::WriteExcel->new('test.xls');
my $worksheet = $workbook->add_worksheet('sample');
#---this works 
processfile($worksheet);
#--this will corrupt excel file , irrespective of worksheet being shared or private.
#threads->new(\&processfile,$worksheet)->join();
$workbook->close();

sub processfile { my($wrksheet)=@_; $wrksheet->write(0, 0, "Hi Excel!"); return  ; }