datetime.py 文件源码

def _fromtimestamp(cls, t, utc, tz):
        """Construct a datetime from a POSIX timestamp (like time.time()).

        A timezone info object may be passed in as well.
        """
        frac, t = _math.modf(t)
        us = round(frac * 1e6)
        if us >= 1000000:
            t += 1
            us -= 1000000
        elif us < 0:
            t -= 1
            us += 1000000

        converter = _time.gmtime if utc else _time.localtime
        y, m, d, hh, mm, ss, weekday, jday, dst = converter(t)
        ss = min(ss, 59)    # clamp out leap seconds if the platform has them
        return cls(y, m, d, hh, mm, ss, us, tz)