use XML::Writer;
use IO::File;
use threads;
use strict;

my $output = new IO::File(">output.xml");

my $writer = new XML::Writer(OUTPUT => $output, DATA_MODE=>1, DATA_INDENT=>1,CHECK_PRINT=>1);

$writer->xmlDecl("UTF-8");




$writer->startTag('operations');

my $thr1 = threads->new(\&writeArticleData1);
my $thr2 = threads->new(\&writeArticleData2);


while (!(($thr1->join) && ($thr2->join)))
{
	# Wait for threads to finish
}

$writer->endTag("operations");
$writer->end();
$output->close();



sub writeArticleData1()
{
	lock($writer);

	$writer->startTag('product');
	$writer->characters("Hello, world!");
	$writer->endTag("product");
	
	sleep 2;
	
	return 1;
	
}

sub writeArticleData2()
{
	lock($writer);

	$writer->startTag('product');
	$writer->characters("Hello, world2!");
	$writer->endTag("product");
	
	return 1;
}

1;

##</code><code>##

<?xml version="1.0" encoding="UTF-8"?>

<operations>
 <product>Hello, world2!</product>
 <product>Hello, world!</product></operations>