From d232af70f2ef150ea41537de50a0ade92ecd7e3a Mon Sep 17 00:00:00 2001
From: Cloud Wu <cloudwu@gmail.com>
Date: Wed, 25 Dec 2019 17:58:03 +0800
Subject: [PATCH] fix #1139

---
 lualib-src/lua-multicast.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/lualib-src/lua-multicast.c b/lualib-src/lua-multicast.c
index 4588bd10..dab90ee2 100644
--- a/lualib-src/lua-multicast.c
+++ b/lualib-src/lua-multicast.c
@@ -141,7 +141,8 @@ static int
 mc_nextid(lua_State *L) {
 	uint32_t id = (uint32_t)luaL_checkinteger(L, 1);
 	id += 256;
-	lua_pushinteger(L, (uint32_t)id);
+	// remove the highest bit, see #1139
+	lua_pushinteger(L, id & 0x7fffffffu);
 
 	return 1;
 }