diff --git a/sys/living/skill_attributes.h b/sys/living/skill_attributes.h
index b6fb7b0..eefd0b1 100644
--- a/sys/living/skill_attributes.h
+++ b/sys/living/skill_attributes.h
@@ -91,8 +91,8 @@
                            string *attr);
 
 // Kompatibilitaetsfunktion mit altem Interface.
-public int    ModifySkillAttributeOld(object caster, string atrname, int value,
-                          int duration, mixed fun);
+public varargs int ModifySkillAttributeOld(object caster, string atrname,
+                     int value, int duration, mixed fun);
 
 #endif // __SKILL_ATTRIBUTES_H_PROTO__