#include #include #include struct test { static int muh_variable; }; int test::muh_variable = 25; int main() { std::cout << "=== static_variables example ===" << std::endl; sol::state lua; lua.open_libraries(); lua.new_usertype("test", "direct", sol::var(2), "global", sol::var(test::muh_variable), "ref_global", sol::var(std::ref(test::muh_variable)) ); int direct_value = lua["test"]["direct"]; // direct_value == 2 assert(direct_value == 2); std::cout << "direct_value: " << direct_value << std::endl; int global = lua["test"]["global"]; int global2 = lua["test"]["ref_global"]; // global == 25 // global2 == 25 assert(global == 25); assert(global2 == 25); std::cout << "First round of values --" << std::endl; std::cout << global << std::endl; std::cout << global2 << std::endl; test::muh_variable = 542; global = lua["test"]["global"]; // global == 25 // global is its own memory: was passed by value global2 = lua["test"]["ref_global"]; // global2 == 542 // global2 was passed through std::ref // global2 holds a reference to muh_variable // if muh_variable goes out of scope or is deleted // problems could arise, so be careful! assert(global == 25); assert(global2 == 542); std::cout << "Second round of values --" << std::endl; std::cout << "global : " << global << std::endl; std::cout << "global2: " << global2 << std::endl; std::cout << std::endl; return 0; }