Thanks Jamie, this will be fixed soon in SVN. See the sourceforge tracker (Comment #2) for more details and updates.
FYI this bug is present in all version of check_ntp (in "plugins/" only) and check_ntp_peer (from which the code was taken), it's just that for some reasons it doesn't get triggered. The SIZEOF_NTPCM formula was broken in the very first versions of check_ntp (note though that very old versions of nagios-plugins shipped a Perl version of check_ntp, found in "plugins-scripts/").
Thanks Jamie, this will be fixed soon in SVN. See the sourceforge tracker (Comment #2) for more details and updates.
FYI this bug is present in all version of check_ntp (in "plugins/" only) and check_ntp_peer (from which the code was taken), it's just that for some reasons it doesn't get triggered. The SIZEOF_NTPCM formula was broken in the very first versions of check_ntp (note though that very old versions of nagios-plugins shipped a Perl version of check_ntp, found in "plugins- scripts/ ").