time(2) -- Linux man page
NAMEtime - get time in seconds
DESCRIPTIONtime returns the time since the Epoch (00:00:00 UTC, January 1, 1970), measured in seconds.
RETURN VALUEOn success, the value of time in seconds since the Epoch is returned. On error, ((time_t)-1) is returned, and errno is set appropriately.
- t points outside your accessible address space.
NOTESPOSIX.1 defines seconds since the Epoch as a value to be interpreted as the number of seconds between a specified time and the Epoch, according to a formula for conversion from UTC equivalent to conversion on the na??ve basis that leap seconds are ignored and all years divisible by 4 are leap years. This value is not the same as the actual number of seconds between the time and the Epoch, because of leap seconds and because clocks are not required to be synchronised to a standard reference. The intention is that the interpretation of seconds since the Epoch values be consistent; see POSIX.1 Annex B 2.2.2 for further rationale.
CONFORMING TOSVr4, SVID, POSIX, X/OPEN, BSD 4.3
Under BSD 4.3, this call is obsoleted by gettimeofday(2). POSIX does not specify any error conditions.
SEE ALSOctime(3), date(1), ftime(3), gettimeofday(2)