From 171c377a0abe12d1418540dc154feccd9355995e Mon Sep 17 00:00:00 2001 From: Bruce Momjian Date: Thu, 6 Nov 2014 02:33:05 -0500 Subject: [PATCH] C comment: mention why the Gregorian calendar is used pre-1582 --- src/include/utils/datetime.h | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/src/include/utils/datetime.h b/src/include/utils/datetime.h index 9b53ee38ccf..548758a1493 100644 --- a/src/include/utils/datetime.h +++ b/src/include/utils/datetime.h @@ -271,6 +271,11 @@ extern const char *const months[]; /* months (3-char abbreviations) */ extern const char *const days[]; /* days (full names) */ extern const int day_tab[2][13]; +/* + * These are the rules for the Gregorian calendar, which was adopted in 1582. + * However, we use this calculation for all prior years as well because the + * SQL standard specifies use of the Gregorian calendar. + */ #define isleap(y) (((y) % 4) == 0 && (((y) % 100) != 0 || ((y) % 400) == 0))