Function long_time_expected_width

src/ls.c:4122–4153

   or zero if it cannot be calculated.  */

static int
long_time_expected_width (void)
{
  static int width = -1;

  if (width < 0)
    {
      time_t epoch = 0;
      struct tm tm;
      char buf[TIME_STAMP_LEN_MAXIMUM + 1];

      /* In case you're wondering if localtime_rz can fail with an input time_t
         value of 0, let's just say it's very unlikely, but not inconceivable.
         The TZ environment variable would have to specify a time zone that
         is 2**31-1900 years or more ahead of UTC.  This could happen only on
         a 64-bit system that blindly accepts e.g., TZ=UTC+20000000000000.
         However, this is not possible with Solaris 10 or glibc-2.3.5, since
         their implementations limit the offset to 167:59 and 24:00, resp.  */
      if (localtime_rz (localtz, &epoch, &tm))
        {
          ptrdiff_t len = align_nstrftime (buf, sizeof buf, false,
                                           &tm, localtz, 0);
          if (len > 0)
            width = mbsnwidth (buf, len, MBSWIDTH_FLAGS);
        }

      if (width < 0)
        width = 0;
    }

  return width;
}

/* Print the user or group name NAME, with numeric id ID, using a
   print width of WIDTH columns.  */