Behaviour of lua_pushlightuserdata metatables across different modules in c

Question

I have been tinkering with the Lua C API and I have stumbled on something that I can't quite figure out on my own.

Well , I am aware that you cannot have multiple lighuserdata with different metatables , but is it possible to have lightuserdata in different C modules with individual mettables even if the pointer is of the same type?

eg.

Module A : lightuserdata points to integer type + Metatable A Module B : lightuserdata pointes to integer type + Metatable B

I hope that Module B wont overwrite the metatable on the lightuserdata in Module A.

Anyone know if this will happen?

Answer 1

Lightuserdata cannot have individual metatables: all lightuserdata values have the same metatable, which is initially nil. If you give a metatable to a lightuserdata value, it will be set to all lightuserdata values.

Having individual metatables is the purpose of ordinary, full userdata. Just use full userdata and don't think twice.