diff --git a/generator/generator.lua b/generator/generator.lua
index e2f03fa..c62a26f 100644
--- a/generator/generator.lua
+++ b/generator/generator.lua
@@ -2,6 +2,7 @@
 --script for auto_funcs.h and auto_funcs.cpp generation
 --expects Lua 5.1 or luajit
 --------------------------------------------------------------------------
+assert(_VERSION=='Lua 5.1',"Must use LuaJIT or Lua5.1")
 local script_args = {...}
 
 --test gcc present