diff --git a/ext/fox16_c/include/gvl_wrappers.h b/ext/fox16_c/include/gvl_wrappers.h
index 44caf974063c62ec0227a1fd3bbc1130745597dd..7873ce2cf32309300fe07ec37da6875e4bbbd0c2 100644
--- a/ext/fox16_c/include/gvl_wrappers.h
+++ b/ext/fox16_c/include/gvl_wrappers.h
@@ -85,7 +85,7 @@ extern __thread int g_fxrb_thread_has_gvl;
 #define FOR_EACH_PARAM_OF_FXImage_savePixels(param) \
   param(FXStream&, store)
 
-/* function( name, void_or_nonvoid, returntype, firstparamtype, firstparamname ) */
+/* function( class, name, baseclass, void_or_nonvoid, returntype, firstparamtype, firstparamname ) */
 #define FOR_EACH_BLOCKING_FUNCTION(function) \
   function(FXImage, loadPixels, FXImage, GVL_TYPE_NONVOID, bool, FXImage *, self) \
   function(FXImage, savePixels, FXImage, GVL_TYPE_NONVOID, bool, const FXImage *, self) \