diff --git a/library/ecp.c b/library/ecp.c
index 30e726a..e8df7ff 100644
--- a/library/ecp.c
+++ b/library/ecp.c
@@ -2818,6 +2818,8 @@
             goto cleanup;
         }
     }
+#else
+    (void) grp_id;
 #endif
 
     /* Final check: check if XmP + 1 is P (final because it changes XmP!) */