diff --git a/glib/gmem.c b/glib/gmem.c
index c4f42c545..b72a58335 100644
--- a/glib/gmem.c
+++ b/glib/gmem.c
@@ -210,7 +210,11 @@ g_free (gpointer mem)
  * pointer is set to %NULL.
  *
  * A macro is also included that allows this function to be used without
- * pointer casts.
+ * pointer casts. This will mask any warnings about incompatible function types
+ * or calling conventions, so you must ensure that your @destroy function is
+ * compatible with being called as `GDestroyNotify` using the standard calling
+ * convention for the platform that GLib was compiled for; otherwise the program
+ * will experience undefined behaviour.
  *
  * Since: 2.34
  **/