std::time_t (3) - Linux Manuals
std::time_t: std::time_t
NAME
Synopsis
Defined in header <ctime>
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
time (function)
localtime (function)
gmtime (function)