Added some comments and reversed upb_arena_cleanup() args.

1 files changed, 1 insertions, 1 deletions

diff --git a/upb/upb.c b/upb/upb.c
index f56f6c4..d8d2723 100644
--- a/upb/upb.c
+++ b/upb/upb.c
@@ -231,7 +231,7 @@ void upb_arena_free(upb_arena *a) {
   }
 }
 
-bool upb_arena_addcleanup(upb_arena *a, upb_cleanup_func *func, void *ud) {
+bool upb_arena_addcleanup(upb_arena *a, void *ud, upb_cleanup_func *func) {
   cleanup_ent *ent = upb_malloc(&a->alloc, sizeof(cleanup_ent));
   if (!ent) {
     return false;  /* Out of memory. */