Defined in header
typedef /* unspecified */ time_t;
Arithmetic type capable of representing times.
Although not defined, this is almost always an integral value holding the number of seconds (not counting leap seconds) since 00:00, Jan 1 1970 UTC, corresponding to POSIX time.
 See also
| returns the current time of the system as time since epoch |
| converts time since epoch to calendar time expressed as local time |
| converts time since epoch to calendar time expressed as Universal Coordinated Time |
C documentation for time_t