static int my_pushcclosure_func(lua_State* L)
{
    std::cout << "Size_L:" <<gettop(L) << std::endl;    //Размер равен нулю.

    std::cout << "PARAM1:" << lua_tostring(L, lua_upvalueindex(1)) << std::endl;    //Тут будет param1
    std::cout << "PARAM2:" << lua_tostring(L, lua_upvalueindex(2)) << std::endl;    //Тут будет param2
}



    lua_pushstring(L, "param1");
    lua_pushstring(L, "param2");
    lua_pushcclosure(L, my_pushcclosure_func, 2);

    int status_lua_pcall = lua_pcall(L, 0, 0, 0);