

GMT                         Definition                        GMT




GMT is an abbreviation  of Greenwich Mean Time, the time recorded
at the  Greenwich Observatory in England,  where by international
convention the Earth's zero meridian is fixed.

By definition, COHERENT  fixes system time in GMT.  It calculates
local time  as an offset of  GMT; for example, the  time zone for
Chicago is six hours (360 minutes) behind Greenwich, so the local
time for  Chicago is calculated  by subtracting 360  minutes from
GMT.

***** See Also *****

definitions, gmtime(), localtime, time, time.h, TIMEZONE

***** Notes *****

The ANSI  Standard replaces GMT  with UTC (_u_n_i_v_e_r_s_e_l  _t_e_m_p_s _c_o_o_r-
_d_o_n_n_e,  or universal  coordinated time)  for C  programming.  The
change  is mainly  one of terminology  rather than  substance, as
some  signatories to international  conventions object  to naming
the standard for global time after a village in England.

Under international convention, there are two UTC standards: UTC1
is based  on solar time and is identical  to current GMT, whereas
UTC2  uses atomic  clocks that are  corrected by  comparison with
pulsars.   These standards  drift apart  as the  earth's rotation
slows; thus, ``leap seconds'' are inserted periodically into UTC1
to bridge the difference.




























COHERENT Lexicon                                           Page 1


