Function main

examples/source/tutorials/quick_n_dirty/userdata_memory_reference.cpp:21–63

};

int main(int, char*[]) {
	std::cout << "=== userdata memory reference ==="
	          << std::endl;

	sol::state lua;
	lua.open_libraries(sol::lib::base);

	Doge dog {}; // Kept alive somehow

	// Later...
	// The following stores a reference, and does not copy/move
	// lifetime is same as dog in C++
	// (access after it is destroyed is bad)
	lua["dog"] = &dog;
	// Same as above: respects std::reference_wrapper
	lua["dog"] = std::ref(dog);
	// These two are identical to above
	lua.set("dog", &dog);
	lua.set("dog", std::ref(dog));


	Doge& dog_ref = lua["dog"];     // References Lua memory
	Doge* dog_pointer = lua["dog"]; // References Lua memory
	Doge dog_copy = lua["dog"]; // Copies, will not affect lua

	lua.new_usertype<Doge>("Doge", "tailwag", &Doge::tailwag);

	dog_copy.tailwag = 525;
	// Still 50
	lua.script("assert(dog.tailwag == 50)");

	dog_ref.tailwag = 100;
	// Now 100
	lua.script("assert(dog.tailwag == 100)");

	dog_pointer->tailwag = 345;
	// Now 345
	lua.script("assert(dog.tailwag == 345)");

	std::cout << std::endl;

	return 0;
}