diff --git a/lib/u_async.c b/lib/u_async.c
index 042c08ab..4000d930 100644
--- a/lib/u_async.c
+++ b/lib/u_async.c
@@ -708,7 +708,7 @@ void* uasync_add_socket(struct UASYNC* ua, int fd, socket_callback_t read_cbk, s
 #endif
     
     DEBUG_DEBUG(DEBUG_CATEGORY_SYS, "socket_add fd=%d name='%s' type=FD r=%p w=%p e=%p ud=%p",
-                fd, name ? name : "?", read_cbk, write_cbk, except_cbk, user_data);
+                fd, name ? name : "?", (void*)read_cbk, (void*)write_cbk, (void*)except_cbk, user_data);
 
     // Return index-based handle
     return (void*)(uintptr_t)(index + 1);