diff --git a/src/basic/unit-def.h b/src/basic/unit-def.h
index 7742c5c078..508b4c504d 100644
--- a/src/basic/unit-def.h
+++ b/src/basic/unit-def.h
@@ -62,7 +62,7 @@ typedef enum UnitMarker {
         UNIT_MARKER_NEEDS_RELOAD,
         UNIT_MARKER_NEEDS_RESTART,
         _UNIT_MARKER_MAX,
-        _UNIT_MARKER_INVALID = -1
+        _UNIT_MARKER_INVALID = -EINVAL,
 } UnitMarker;
 
 typedef enum AutomountState {