diff --git a/src/event_system.c b/src/event_system.c
index 8f593fd..dbd9618 100644
--- a/src/event_system.c
+++ b/src/event_system.c
@@ -329,8 +329,8 @@ internal void copy_event_data(const ESInternal *src, ESInternal *dst) {
     ev_dst->count      = ev_src->count;
     ev_dst->free_count = ev_src->free_count;
 
-    memcpy((void *)(ev_dst->free), (void *)(ev_src->free), FREE_CB_ARR_SIZE(ev_src->capacity));
-    memcpy((void *)(ev_dst->callbacks), (void *)(ev_src->callbacks), CB_ARR_SIZE(ev_src->capacity));
+    memcpy((void *)(ev_dst->free), (const void *)(ev_src->free), FREE_CB_ARR_SIZE(ev_src->capacity));
+    memcpy((void *)(ev_dst->callbacks), (const void *)(ev_src->callbacks), CB_ARR_SIZE(ev_src->capacity));
   }
 }