use feature qw( :5.10 );

sub uncalled_sub {
    state $huge = huge_data_structure();
    return;
}

print 'mem usage: ', my_mem(), "\n";

sub huge_data_structure {
    return [ ( 'x' x 1_000 ) x 100_000 ];
}
sub my_mem {
    my ($proc_info)
        = grep { $_->[2] == $$ } map { [ split ] } `ps l | tail -n +2`;
    return $proc_info->[6];
}
__END__
mem usage: 11220

##</code><code>##

{
    my $huge = huge_data_structure();
    sub uncalled_sub {
#        state $huge = huge_data_structure();
        return;
    }
}

print 'mem usage: ', my_mem(), "\n";
__END__
mem usage: 116132

##</code><code>##

print counter(), "\n";
{   
    my $count = 0;
    sub counter { $count++ }
}
print counter(), "\n";
__END__
0
0

##</code><code>##

use feature qw( :5.10 );

print counter(), "\n";
sub counter {
    state $count = 0;
    return $count++;
}
print counter(), "\n";
__END__
0
1