Re: unix epoch data wrapping

[<pl...@pi...>]

On 03/27/10 20:27, sfeam (Ethan Merritt) wrote:
> On Saturday 27 March 2010, pl...@pi... wrote:
>> On 03/27/10 16:31, Jonathan Thornburg wrote:
>
>>> 2-digit years are fundamentally ambiguous, so some (arbitrary) decision
>>> must be made to resolve that ambiguity.  I'm not sure how gnuplot implements
>>> this internally, but The X/Open standard documents a function  strptime()
>>> whose man page on my computer says
>>> |      %y    the year within the current century.  When a century is not other-
>>> |            wise specified, values in the range 69-99 refer to years in the
>>> |            twentieth century (1969 to 1999 inclusive); values in the range
>>> |            00-68 refer to years in the twenty-first century (2000 to 2068 in-
>>> |            clusive).  Leading zeros are permitted but not required.
>
>  From the gnuplot source file time.c:
>
>          case 'y':               /* year number */
>              s = read_int(s, 2,&tm->tm_year);
>              /* In line with the current UNIX98 specification by
>               * The Open Group and major Unix vendors,
>               * two-digit years 69-99 refer to the 20th century, and
>               * values in the range 00-68 refer to the 21st century.
>               */
>              if (tm->tm_year<= 68)
>                  tm->tm_year += 100;
>              date++;
>              tm->tm_year += 1900;
>              break;
>
>
>
Thanks Ethan,

shouldn't the doc as well as the source indicate this oddity?

regards.