struct tm *
offtime(const time_t * clock, long int offset)
time_t
timeoff(struct tm * tm, long int offset)
time_t
timegm(struct tm * tm)
time_t
timelocal(struct tm * tm)
offtime()
converts the calendar time
clock,
offset by
offset
seconds,
into broken-down time, expressed as Coordinated Universal Time (UTC).
timeoff()
converts the broken-down time
tm,
expressed as UTC,
offset by
offset
seconds,
into a calendar time value.
timegm()
converts the broken-down time
tm
into a calendar time value, effectively being the inverse of
gmtime(3).
It is equivalent to the C standard function
mktime(3)
operating in UTC.
timelocal()
converts the broken down time
tm,
expressed as local time, into a calendar time value.
It is equivalent to the C standard function
mktime(3),
and is provided for symmetry only.