#!/usr/bin/perl

use strict;
use warnings;
use threads;
use POSIX qw(tzset);

my $t=localtime();
print "local time: ",$t,"\n";

my ($tr) = threads->create(\&thr_proc);

$tr->join;

$ENV{TZ}="Europe/Paris";
$t=localtime();
print "main: ",$t,"\n";

$ENV{TZ}="Europe/Moscow";
$t=localtime();
print "main: ",$t,"\n";

sub thr_proc {

    $ENV{TZ} = 'Europe/Paris';
    $t = localtime;
    print "in thread: ",$t,"\n";

    $ENV{TZ} = 'Europe/Moscow';
    $t = localtime;
    print "in thread: ",$t,"\n";
}