--- a/src/lib/StarGraphicStruct.cxx
+++ b/src/lib/StarGraphicStruct.cxx
@@ -152,7 +152,7 @@
 {
   if (!pattern) return false;
   STOFFVec2i sz(8,8);
-  unsigned tmpBufferPosition, tmpDIBFileSize;
+  unsigned tmpBufferPosition, tmpDIBFileSize = 0;
   auto tmpDIBBuffer=createAndInitBMPData(sz, tmpDIBFileSize, tmpBufferPosition);
   if (!tmpDIBBuffer) return false;