Re: lua_lock/lua_unlock

["Ashwin Hirschi" <deery@...>]

> I'm porting a video game that uses Lua 5.0. The interpreter frequently
> crashes on startup and the evidence points to a reference counting bug
> or perhaps simple data corruption. The game uses true preemptive
> threads, but Lua is only called from the main thread, and I understand
> that within Lua "threads" are just cooperative coroutines.

The lua_lock/lua_unlock pair is there to help synchronise access to Lua states.

Typically, in a scenario where multiple (OS) threads need access to the same Lua state, you'll have to redefine these primitives to something sensible, like locking/unlocking a mutex (or somesuch).

But in your case, it looks like you can leave things as they are, since access from one OS thread is safe.

I'm not sure what you meant by (possible) reference counting bug, though. If I'm not mistaken Lua doesn't use any reference counting...

Anyways, if you suspect the crash during startup is somehow Lua-related, it might be a good idea to review the code that registers the various custom Lua primitives (if any). If the custom init code is sloppy it could (perhaps?) overflow the (Lua VM) stack.

Good luck hunting down that bug!

Ashwin.
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