Re: Crash in a library when un loading.

[Roberto Ierusalimschy <roberto@...>]

> Hi everyone. I'm experiencing a crash when a C module is unloaded. I think I
> know what is the cause but it seems strange that it is failing.
> 
> Part of the relevant code below:
> 
> static int module_cleanup(lua_State* L) {
>   return 0;
> }
> 
> extern "C" __declspec(dllexport) int luaopen_mymodule(lua_State* L) {
>   /* env.__gc = module_cleanup */
>   lua_pushcclosure(L, module_cleanup, 0);
>   lua_setfield(L, LUA_ENVIRONINDEX, "__gc");
> 
>   lua_newtable(L);
>   return 1;
> }
> 
> 
> The thing is that when the Lua state is closed, the module is unloaded first
> and then the function 'module_cleanup' is (tried to be) called.

Is this what is happening or what you think it is happening?


> Obviously, when I don't assign a __gc field to the environment the problem
> does not occur.
> 
> Does this mean that the environment is its own metatable? If not, is this a
> bug?

Even if the environment was its own metatable it would not matter, because
tables do not call __gc methods. Is the environment a metatable for some
userdata?

-- Roberto