$watchObject = $inotify->watch (
  "/var/log/snmptrapd.log", IN_MODIFY,  &processTrap()  );
or
  "/var/log/snmptrapd.log", IN_MODIFY,  processTrap()  );
or
  "/var/log/snmptrapd.log", IN_MODIFY,  sub{ processTrap() }  );