Pass userdata object as argument to __gc function?

[bit-garden]

I'm currently working with Raylib which is written in C. It relies on the developer to manually unload resources.

In the example of Texture2d, I would like to define __gc to clean it up automatically when used from Lua, but the reference to the userdata object gets lost.

Example:

luaTexture2d.def("__gc", [](Texture2d& self){ unloadTexture(self);});

__gc is not called in this case unless no arguments are passed.

Unless I'm missing something. I would have to add a GC function to the struct and then bind it that way, but this would break on upstream updates.

I also tried adding the destructor through the .ctor function but this throws a type error.

[gengyong]

For exported LuaClasses, instances created in the Lua environment will call the destructor of the exported class during garbage collection. You can invoke the cleanup function in the destructor of the exported class.

Another approach is to define a managed constructor function, provide a spawner method for creating instances and a delete function for destroying them. In the delete function, execute the cleanup function and delete the object instance.

example：

class SingletonWorld 
{
public:
    static SingletonWorld * getInstance() {
        static SingletonWorld instance("singleton");
        return &instance;
    }

    static SingletonWorld * newInstance(const std::string tagName) {
        return new SingletonWorld(tagName);
    }

    static void delInstance(SingletonWorld * instance) {

        // Your codes goes here ...

        delete instance;
    }
public:
}

LuaClass<SingletonWorld> luaWorld(L, "SingletonWorld");
luaWorld.ctor("managedInstance", &SingletonWorld::newInstance , &SingletonWorld::delInstance);