On Thu, Apr 12, 2007 at 10:34:25PM +0200, Maurice Janssen wrote: > The manpage for rdate(8) uses the -c option in the examples at the > bottom (leap second correction), but the given host (ptbtime1.ptb.de) > doesn't need this.
SNTP gives time in UTC, but some sysadmins would prefer to synchronize their system time to TAI rather than UTC (e.g., so time values returned by gettimeofday(2) progresses normally during leap seconds). The -c argument for rdate is intended for their use. Basic rule of thumb is use -c if and only if you're using a timezone file under /usr/share/zoneinfo/right/ (i.e., one that includes leap second info). Otherwise your clock will most likely be off by 23 seconds.
