Go forward to localtime
Go backward to difftime
Go up to Timefns
Go to the top op libc

`gmtime'--convert time to UTC traditional form

     #include <time.h>
     struct tm *gmtime(const time_t *CLOCK);
     struct tm *gmtime_r(const time_t *CLOCK, struct tm *RES);
`gmtime' assumes the time at CLOCK represents a local time.  `gmtime'
converts it to UTC (Universal Coordinated Time, also known in some
countries as GMT, Greenwich Mean time), then converts the
representation from the arithmetic representation to the traditional
representation defined by `struct tm'.
   `gmtime' constructs the traditional time representation in static
storage; each call to `gmtime' or `localtime' will overwrite the
information generated by previous calls to either function.
A pointer to the traditional time representation (`struct tm').
ANSI C requires `gmtime'.
   `gmtime' requires no supporting OS subroutines.