Index: src/libcfa/iostream.c
===================================================================
--- src/libcfa/iostream.c	(revision 233e4d9b6c11222533f75c7e90ac84e0e527d6b9)
+++ src/libcfa/iostream.c	(revision 2c4bc8114e8d7626b9a63138e95d0072d839e1e1)
@@ -203,4 +203,5 @@
 	os | arg | ", ";
 	os | rest;
+	return os;
 } // ?|?