Oh! If you'll be adding to the keylist, you should use a different approach:

while (1) {
  my @todo = grep ! defined $links{$_}{something}, keys %links or last
+;
  while (@todo) {
    my $one = shift @todo;
    # process $links{$one}
  }
}
[download]

This presumes that something eventually defines all the "something" keys. If not, you need to use a sweeping strategy instead: I've done that for one of my link checker columns.

-- Randal L. Schwartz, Perl hacker