From cd1e5d8dfdbcd86b793c4460df5436e2a8b48ee4 Mon Sep 17 00:00:00 2001
From: Daniel Kulp <dan@kulp.com>
Date: Wed, 4 Sep 2019 19:02:07 +0000
Subject: [PATCH] Fix for if no data to send

---
 src/VASTFMT.cpp | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/VASTFMT.cpp b/src/VASTFMT.cpp
index 630d154..0c69c6b 100755
--- a/src/VASTFMT.cpp
+++ b/src/VASTFMT.cpp
@@ -158,7 +158,9 @@ bool VASTFMT::sendSi4711Command(uint8_t cmd, const std::vector<uint8_t> &dataIn,
     aucBufOut[2] = RequestSi4711Access;
     aucBufOut[3] = dataIn.size() + 1;
     aucBufOut[4] = cmd;
-    memcpy(&aucBufOut[5], &dataIn[0], dataIn.size());
+    if (dataIn.size() > 0) {
+        memcpy(&aucBufOut[5], &dataIn[0], dataIn.size());
+    }
 
     hid_write(phd, aucBufOut, 43);
     int r = hid_read(phd, aucBufIn, 42);