use strict;
use threads;
use threads::shared;

my %hash = (
	'a' => 'foo',
	'b' => 'foo',
	'c' => 'foo',
	'd' => 'foo'
);
share($hash{$_}) foreach('a'..'f');
my $tid = 0;
foreach my $key('a'..'f') {
	if(exists $hash{$key}) {
		if(defined $hash{$key}) {
			print "$key => $hash{$key} in thread $tid\n";
		}
		else {
			print "$key => undef in thread $tid\n";
		}
	}
	else {
		print "$key does not exist in thread $tid\n";
	}
}

my $th1 = async {
	$tid = 1;
	print "thread $tid started\n";
	sleep 2;
	foreach my $key('a'..'f') {
		if(exists $hash{$key}) {
			if(defined $hash{$key}) {
				print "$key => $hash{$key} in thread $tid\n";
			}
			else {
				print "$key => undef in thread $tid\n";
			}
		}
		else {
			print "$key does not exist in thread $tid\n";
		}
	}
	print "delete b from thread $tid\n";
	delete $hash{'b'};
	print "undefine d from thread $tid\n";
	undef $hash{'d'};
	print "setting f => foo in thread $tid\n";
	$hash{'f'} = 'foo';
};
my $th2 = async {
	$tid = 2;
	print "thread $tid started\n";
	sleep 3;
	foreach my $key('a'..'f') {
		if(exists $hash{$key}) {
			if(defined $hash{$key}) {
				print "$key => $hash{$key} in thread $tid\n";
			}
			else {
				print "$key => undef in thread $tid\n";
			}
		}
		else {
			print "$key does not exist in thread $tid\n";
		}
	}
};
sleep 1;
print "delete a from thread $tid\n";
delete $hash{'a'};
print "undefine c from thread $tid\n";
undef $hash{'c'};
print "setting e => foo in thread $tid\n";
$hash{'e'} = 'foo';
$th1->join();
$th2->join();
foreach my $key('a'..'f') {
	if(exists $hash{$key}) {
		if(defined $hash{$key}) {
			print "$key => $hash{$key} in thread $tid\n";
		}
		else {
			print "$key => undef in thread $tid\n";
		}
	}
	else {
		print "$key does not exist in thread $tid\n";
	}
}

##</code><code>##

a => foo in thread 0
b => foo in thread 0
c => foo in thread 0
d => foo in thread 0
e => undef in thread 0
f => undef in thread 0
thread 1 started
thread 2 started
delete a from thread 0
undefine c from thread 0
setting e => foo in thread 0
a => foo in thread 1
b => foo in thread 1
c => undef in thread 1
d => foo in thread 1
e => foo in thread 1
f => undef in thread 1
delete b from thread 1
undefine d from thread 1
setting f => foo in thread 1
a => foo in thread 2
b => foo in thread 2
c => undef in thread 2
d => undef in thread 2
e => foo in thread 2
f => foo in thread 2
a does not exist in thread 0
b => foo in thread 0
c => undef in thread 0
d => undef in thread 0
e => foo in thread 0
f => foo in thread 0