freebsd-src/usr.sbin/xntpd/adjtime

------------------------------------------------------------------------------
The adjtimed daemon emulates the BSD adjtime(2) system call.  The
adjtime() routine communicates with this daemon via SYSV messages.

The emulation uses an undocumented kernel variable (as of 6.0/2.0
and later releases) and as such it cannot be guaranteed to work in
future HP-UX releases.  Perhaps HP-UX will have a real adjtime(2)
system call in the future.

Author: Tai Jin (tai@sde.hp.com)
------------------------------------------------------------------------------

IMPORTANT NOTE: This stuff must be compiled with no optimization !!

NOTE: This code is known to work as of 8.0 on s300's, s700's and s800's.
      PLEASE do not modify it unless you have access to kernel sources
      and fully understand the implications of any changes you are making.
      One person already has trashed adjtimed by making it do "the right 
      thing".  This is not an exact replacement for BSD adjtime(2), don't
      try to make it into one.

	 -- Ken