diff --git a/src/policy.hpp b/src/policy.hpp
index d05731c6..68961023 100644
--- a/src/policy.hpp
+++ b/src/policy.hpp
@@ -193,6 +193,7 @@ namespace mergerfs
 
     static const Policy &invalid;
     static const Policy &all;
+    static const Policy &einval;
     static const Policy &enosys;
     static const Policy &enotsup;
     static const Policy &epmfs;