How to set /dev/rtc (real time clock) from UNIX

[joel m. cook]

The man page rtc(7) claims that I can set the real time
clock using the iocctl call RTCSTIME.  While I've been
able to read the clock (using ioctl and RTCRTIME), I've
not been able to set it, even as the super-user.  Anyone
know what legerdemain has to be performed to do so?
Presumably the clock has to have its update turned off, then
set and then restarted and I don't know if I have to do that
or it's take care of by the ioctl call.
Thanks for any help!
-- 
			Joel M. Cook
			jmcook at jorel.apldmt.com