.. efun:: int mktime(int *ts)
  :include: <time.h>

  If the argument :arg:`ts` is an array with 9 elements (int) according to the result of :efun:`localtime` or :efun:`gmtime`, this function returns the number of seconds passed since the epoch (``00:00:00 UTC, January 1, 1970``). This can be used to store a date or time as an integer value or to compute differences betweens two different dates or times.

  The array :arg:`ts` has to have the following structure:

  =========================  =================================
  place                      contains
  =========================  =================================
  int :macro:`TM_SEC`   (0)  Seconds (0..59)
  int :macro:`TM_MIN`   (1)  Minutes (0..59)
  int :macro:`TM_HOUR`  (2)  Hours (0..23)
  int :macro:`TM_MDAY`  (3)  Day of the month (1..31)
  int :macro:`TM_MON`   (4)  Month of the year (0..11)
  int :macro:`TM_YEAR`  (5)  Year (e.g. 2001)
  int :macro:`TM_WDAY`  (6)  Day of the week (Sunday = 0)
  int :macro:`TM_YDAY`  (7)  Day of the year (0..365)
  int :macro:`TM_ISDST` (8)  TRUE during daylight saving time
  =========================  =================================

  :macro:`TM_YDAY` and :macro:`TM_WDAY` are ignored and can contain arbitrary integer values.

  .. usage::

    A date and time (user input) shall be stored as unix timestamp. In the below example, ``unixtime`` holds the unix timestamp corresponding to "Wed Oct 24 10:48:00 2007"::

      int unixtime = mktime( ({0, 48, 09, 24, 09, 2007, 0, 01, 0}) );

  :history 3.3.718 introduced:

  .. seealso:: :efun:`ctime`, :efun:`gmtime`, :efun:`localtime`, :efun:`time`, :efun:`utime`