diff --git a/src/lib/condition.h b/src/lib/condition.h
index 066c6b267..ffc00523c 100644
--- a/src/lib/condition.h
+++ b/src/lib/condition.h
@@ -167,7 +167,7 @@ lumiera_conditionacquirer_wait (LumieraConditionacquirer self)
  * a conditionacquirer must be unlocked before leaving scope
  * @param self conditionacquirer associated with a condition variable
  */
-static inline int
+static inline void
 lumiera_conditionacquirer_unlock (LumieraConditionacquirer self)
 {
   REQUIRE (self);
@@ -195,7 +195,7 @@ lumiera_conditionacquirer_signal (LumieraConditionacquirer self)
  * signal all waiting threads
  * @param self conditionacquirer associated with the condition variable to be signaled
  */
-static inline int
+static inline void
 lumiera_conditionacquirer_broadcast (LumieraConditionacquirer self)
 {
   REQUIRE (self);