2.3.18 void set_system_time

void set_system_time(time_t timestamp)

Initialize the system time. Examples are...

From a Clock / Calendar type RTC:
        struct tm rtc_time;

        read_rtc(&rtc_time);
        rtc_time.tm_isdst = 0;
        set_system_time( mktime(&rtc_time) );
From a Network Time Protocol time stamp:
        set_system_time(ntp_timestamp - NTP_OFFSET);
From a UNIX time stamp:
        set_system_time(unix_timestamp - UNIX_OFFSET);