From 3d388a0a9617036eccda8d5df9c077207431ba1c Mon Sep 17 00:00:00 2001
From: Jef Driesen <jef@libdivecomputer.org>
Date: Sun, 16 Oct 2022 21:29:49 +0200
Subject: [PATCH] Don't pass a NULL pointer to memcpy

The memcpy and related functions expects a valid pointer, even if the
size is zero. Most libc implementations will handle a NULL pointer just
fine, but that's not guaranteed.

Simply skip the call when there is nothing to copy.
---
 src/deepsix_excursion.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/deepsix_excursion.c b/src/deepsix_excursion.c
index 378e20f..53135de 100644
--- a/src/deepsix_excursion.c
+++ b/src/deepsix_excursion.c
@@ -163,7 +163,9 @@ deepsix_excursion_recv (deepsix_excursion_device_t *device, unsigned char grp, u
 		return DC_STATUS_PROTOCOL;
 	}
 
-	memcpy(data, packet + 4, len);
+	if (len) {
+		memcpy(data, packet + 4, len);
+	}
 
 	if (actual)
 		*actual = len;