From 221b377f09a30dd7c74c26c8c1db439afcc59141 Mon Sep 17 00:00:00 2001 From: Robert Haas Date: Mon, 13 May 2019 13:13:24 -0400 Subject: [PATCH] Improve comment for att_isnull. The comment implies that a 1 in the null bitmap indicates a null value, but actually a 0 in the null bitmap indicates a null value. Try to be more clear. Patch by me; proposed wording reviewed by Alvaro Herrera and Tom Lane. Discussion: http://postgr.es/m/CA+TgmobHOP8r6cG+UnsDFMrS30-m=jRrCBhgw-nFkn0k9QnFsg@mail.gmail.com --- src/include/access/tupmacs.h | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/src/include/access/tupmacs.h b/src/include/access/tupmacs.h index 7c62cf3bbc..23cf481e78 100644 --- a/src/include/access/tupmacs.h +++ b/src/include/access/tupmacs.h @@ -16,7 +16,9 @@ /* - * check to see if the ATT'th bit of an array of 8-bit bytes is set. + * Check a tuple's null bitmap to determine whether the attribute is null. + * Note that a 0 in the null bitmap indicates a null, while 1 indicates + * non-null. */ #define att_isnull(ATT, BITS) (!((BITS)[(ATT) >> 3] & (1 << ((ATT) & 0x07))))