1 files changed, 3 insertions, 0 deletions
diff --git a/main.c b/main.c
index 90b3e92c..2bfa5c20 100644
--- a/main.c
+++ b/main.c
@@ -120,6 +120,9 @@ argp_parser (int key, char *arg, struct argp_state *state)
     case NOSUID_KEY:
       /* Ignored for compatibility with Linux' procfs. */
       ;;
+
+    default:
+      return ARGP_ERR_UNKNOWN;
   }
 
   return 0;