sub presenceCB {
  my $sid = shift;
  my $presence = shift;
  my $from = $presence->GetFrom();
  my $type = $presence->GetType();
  my $show = $presence->GetShow();
  my $status = $presence->GetStatus();
  print "$from is now $show/$status\n";
}

Example 4: Jabber and Perl. Structure of the presence function.