Index: src/libcfa/iostream.c
===================================================================
--- src/libcfa/iostream.c	(revision 9c313496292e447189530c6d9e91a7b120e46cc2)
+++ src/libcfa/iostream.c	(revision a53e10a137167a159802005de2655dfb126bf585)
@@ -203,4 +203,5 @@
 	os | arg | ", ";
 	os | rest;
+	return os;
 } // ?|?