public function cron()
 {
     global $DB;
     if ($DB->count_records('user_preferences', array('name' => 'iomad_send_password', 'value' => '1'))) {
         mtrace('creating passwords for new users');
         $newusers = $DB->get_records_sql("SELECT u.id as id, u.email, u.firstname,\n                                                     u.lastname, u.username,\n                                                     p.id as prefid,\n                                                     p.value as prefvalue\n                                                FROM {user} u\n                                                JOIN {user_preferences} p ON u.id=p.userid\n                                                JOIN {user_preferences} p2 ON u.id=p2.userid\n                                               WHERE p.name='iomad_temporary'\n                                                 AND u.email !=''\n                                                 AND p2.name='iomad_send_password'\n                                                 AND p2.value='1' ");
         mtrace('sending passwords to ' . count($newusers) . ' new users');
         foreach ($newusers as $newuserid => $newuser) {
             // Email user.
             if ($this->mail_password($newuser, company_user::rc4decrypt($newuser->prefvalue))) {
                 // Remove user pref.
                 unset_user_preference('iomad_send_password', $newuser);
             } else {
                 trigger_error("Could not mail new user password!");
             }
         }
     }
 }