diff --git a/common/rfb/CMsgReader.cxx b/common/rfb/CMsgReader.cxx
index c325d48..0271936 100644
--- a/common/rfb/CMsgReader.cxx
+++ b/common/rfb/CMsgReader.cxx
@@ -221,7 +221,7 @@
   rdr::U8 buf[width*height*4];
   rdr::U8* out;
 
-  if (width * height) {
+  if (width * height > 0) {
     pr = is->readU8();
     pg = is->readU8();
     pb = is->readU8();
diff --git a/common/rfb/SMsgWriter.cxx b/common/rfb/SMsgWriter.cxx
index 2d4998b..6ef7692 100644
--- a/common/rfb/SMsgWriter.cxx
+++ b/common/rfb/SMsgWriter.cxx
@@ -528,7 +528,7 @@
   os->writeU16(width);
   os->writeU16(height);
   os->writeU32(pseudoEncodingXCursor);
-  if (width * height) {
+  if (width * height > 0) {
     os->writeU8(255);
     os->writeU8(255);
     os->writeU8(255);