my %hash1 = ( one => 1, two => 2 );

check_limit(\%hash1, '%hash1');

sub check_limit {
  my $href = $_[0];
  my $name = $_[1];

  my $num = 0; for (keys %{$href}) { $num++ };
  print "Hash '$name' has $num keys\n";
}
[download]