diff --git a/src/ifcgeom_schema_agnostic/GeometrySerializer.h b/src/ifcgeom_schema_agnostic/GeometrySerializer.h
index 63b1507d97..33012b0b99 100644
--- a/src/ifcgeom_schema_agnostic/GeometrySerializer.h
+++ b/src/ifcgeom_schema_agnostic/GeometrySerializer.h
@@ -77,6 +77,7 @@ public:
 
 	stream_or_filename(const std::string& fn)
 		: ofs_(new std::ofstream(IfcUtil::path::from_utf8(fn).c_str()))
+		, filename_(fn)
 		, stream(*ofs_)
 	{}