>From 9f212e1cdaaee50607b7c577747fed35c571dab0 Mon Sep 17 00:00:00 2001
From: Paul Eggert <address@hidden>
Date: Wed, 18 Dec 2019 16:02:54 -0800
Subject: [PATCH] Fix memcpy issue found by -fsanitize=undefined

* field.c (set_record): Don't memcpy (databuf, NULL, 0),
as the C standard says the resulting behavior is undefined.
---
 ChangeLog | 6 ++++++
 field.c   | 4 +++-
 2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/ChangeLog b/ChangeLog
index e9a543e0..25344e9e 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2019-12-18  Paul Eggert  <address@hidden>
+
+	Fix memcpy issue found by -fsanitize=undefined
+	* field.c (set_record): Don't memcpy (databuf, NULL, 0),
+	as the C standard says the resulting behavior is undefined.
+
 2019-11-21         Arnold D. Robbins     <address@hidden>
 
 	* config.rpath: Update from GNULIB.
diff --git a/field.c b/field.c
index 8c7fe18e..28891c85 100644
--- a/field.c
+++ b/field.c
@@ -288,7 +288,9 @@ set_record(const char *buf, int cnt, const awk_fieldwidth_info_t *fw)
 		memset(databuf, '\0', databuf_size);
 	}
 	/* copy the data */
-	memcpy(databuf, buf, cnt);
+	if (cnt != 0) {
+		memcpy(databuf, buf, cnt);
+	}
 
 	/*
 	 * Add terminating '\0' so that C library routines
-- 
2.23.0