diff --git a/src/arena.c b/src/arena.c
index 648ee84..ee55989 100644
--- a/src/arena.c
+++ b/src/arena.c
@@ -794,7 +794,7 @@ bool _mi_arena_segment_clear_abandoned(mi_segment_t* segment )
 // clears the thread_id.
 void _mi_arena_segment_mark_abandoned(mi_segment_t* segment) 
 {
-  mi_atomic_store_release(&segment->thread_id, 0);
+  mi_atomic_store_release(&segment->thread_id, (uintptr_t)0);
   mi_assert_internal(segment->used == segment->abandoned);
   if (segment->memid.memkind != MI_MEM_ARENA) {
     // not in an arena; count it as abandoned and return