diff --git a/nse_db.cc b/nse_db.cc
index e268d59db..75da118c7 100644
--- a/nse_db.cc
+++ b/nse_db.cc
@@ -99,7 +99,7 @@ static int l_getprotbyname (lua_State *L)
   return 1;
 }
 
-int luaopen_db (lua_State *L)
+LUALIB_API int luaopen_db (lua_State *L)
 {
   static const luaL_Reg dblib [] = {
     {"mac2corp", l_mac2corp},